MRI Findings in a Rottweiler with …...CASE REPORTS MRI Findings in a Rottweiler with Leukoencephalomyelopathy Joseph S. Eagleson, DVM, DACVIM (Neurology)*, Marc Kent, DVM, DACVIM

CASE REPORTS

MRI Findings in a Rottweiler withLeukoencephalomyelopathyJoseph S. Eagleson, DVM, DACVIM (Neurology)*, Marc Kent, DVM, DACVIM (Neurology), Simon R. Platt, BVM&S, DECVN,

DACVIM (Neurology), Raquel R. Rech, DVM, DACVP, PhDy, Elizabeth W. Howerth, DVM, DACVP, PhD

ABSTRACTA 22mo oldmale rottweiler presented with a 1 mo progressive history of general proprioceptive ataxia and upper motor neuron

tetraparesis. Neurologic examination was consistent with a lesion affecting the first through fifth cervical spinal cord segments.

MRI disclosed bilaterally symmetric hyperintensities on T2-weighted (T2W) images in the crus cerebri and pyramidal tracts

of the brain and the dorsal portion of the lateral funiculi of the cervical spinal cord. Fifty days after initial presentation, the

dog was euthanized due to disease progression. Pathologic examination of the central nervous system (CNS) revealed a bi-

laterally symmetric chronic leukoencephalomyelopathy (LEM) consistent with previous reports of LEM in rottweilers. To the

authors’ knowledge, this is the first report to describe the MRI characteristics of LEM in the rottweiler. The topography of the

changes observed with MRI paralleled the pathologic changes, which were widespread loss of myelin, decreased axon

numbers, and astroglial proliferation. Consequently, MRI of the CNS of affected rottweilers may aid in establishing a presumptive

antemortem diagnosis of LEM. (J Am Anim Hosp Assoc 2013; 49:255–261. DOI 10.5326/JAAHA-MS-5864)

IntroductionLeukoencephalomyelopathy (LEM) in the rottweiler is a rare de-

generative disorder that has been recognized since the early

1980s.1–3 The clinical syndrome manifests as a long-strided gait

with the appearance of stiffness and overreaching as the limbs are

advanced when walking, consistent with general proprioceptive

ataxia and upper motor neuron tetraparesis that begins between

1.5 and 3.5 yr of age.3 Affected dogs initially develop abnormal-

ities in the thoracic limbs, and the thoracic limbs are often more

severely affected than the pelvic limbs. Gender predilection has

not been reported. Despite a familial relationship among affected

dogs, a mode of inheritance has not been determined.1–3 The

etiology of LEM remains unknown. Progression of clinical signs

occurs over months to up to a year, with most dogs being eu-

thanized due to increased difficulty ambulating.2 Currently, the

antemortem diagnosis is based on exclusion of other diseases that

result in similar clinical signs, and diagnosis often entails ad-

vanced imaging. To the authors’ knowledge, this is the first report

to describe the MRI characteristics of LEM in the rottweiler. In

the present case, the topography of the lesions observed with MRI

exactly paralleled the pathologic changes observed on gross and

microscopic examination of the central nervous system (CNS),

which consisted of severe myelin loss, decreased axonal numbers,

astrogliosis, and astrocytosis. Consequently, MRI of the nervous

system may aid clinicians in establishing a presumptive ante-

mortem diagnosis of LEM in rottweilers.

Case ReportA 22 mo old male rottweiler presented to the Veterinary Teaching

Hospital, University of Georgia with a 1 mo progressive history of

From the Department of Small Animal Medicine and Surgery (J.E., M.K.,

S.P.) and Department of Pathology (R.R., E.H.), University of Georgia,

Athens, GA.

Correspondence: [email protected] (M.K.)

MBP myelin basic protein; CNS central nervous system; FLAIR fluid-

attenuated inversion recovery; GFAP glial fibrillary acidic protein; LEM leuko-

encephalomyelopathy; NAD neuroaxonal dystrophy; T1W T1-weighted; T2W

T2-weighted; T2*W T2*-weighted gradient echo

*J. Eagleson’s present affiliation is Veterinary Specialty & Emergency Center,

Levittown, PA.

†R. Rech’s present affilitation is Brazilian Agricultural Research Corp

(EMBRAPA), Concordia, Brazil.

ª 2013 by American Animal Hospital Association JAAHA.ORG 255

mailto:[email protected]

an abnormal gait. The dog was current on vaccinations and was

receiving heartworm preventativemonthly. There was no history of

other medical problems. Physical examination was normal. On

neurologic examination, the dog displayed a longer than normal

stride that was characterized by stiffness and overreaching, con-

sistent with general proprioceptive ataxia and upper motor neuron

paresis in all four limbs. The gait was characterized by hypermetria

resulting in marked overreaching in the thoracic limbs. The dog

scuffed the nails on all four feet while walking. Deficits in postural

reactions (proprioceptive placing and hopping) were observed in

all four limbs. Deficits were worse in the thoracic limbs. Addi-

tionally, the left thoracic and pelvic limbs were more affected than

the right thoracic and pelvic limbs. Spinal reflexes were normal in

the thoracic limbs. In the pelvic limbs, the withdrawal reflexes were

normal and patella reflexes were increased bilaterally. Muscle mass

and muscular tone were both normal in all four limbs. Cranial

nerve examination was normal. There was normal range of motion

of the neck. The dog did not appear painful with either manip-

ulation or palpation along the entire vertebral column. Neuro-

anatomic diagnosis was consistent with a lesion affecting the first

through fifth cervical spinal cord segments. Differential diagnoses

included cervical vertebra(e) malformation/malarticulation, inter-

vertebral disc disease, fibrotic stenosis, subarachnoid diverticula,

neoplasia, LEM, and neuroaxonal dystrophy (NAD).

Hematologic and serum biochemical examinations revealed

lymphocytosis (3.33 103/mL; reference range, 0 0.4–2.93 103/mL)

and eosinophilia (1.53 3 103/mL; reference range, 0–1.3 3 103/mL).

Urinalysis was normal. Under anesthesia, MRI of the vertebral

column from the first cervical vertebra to the third thoracic

vertebra and the brain was performed using a 3.0T MR unita

and a multichannel phase array spine coil. The following pulse

sequences were obtained: T1-weighted fluid-attenuated inversion

recovery (T1W FLAIR), T2-weighted (T2W), T2-weighted FLAIR

(T2W FLAIR), and T2*-weighted gradient echo (T2*W) images.

Additionally, axial and sagittal plane T1W FLAIR images of the

vertebral column and the brain were obtained after IV adminis-

tration (0.1 mmol/kg) of contrast agentb.

In comparison with unaffected white matter of the spinal

cord, bilaterally symmetric intra-axial hyperintensities on T2W

images were noted in the white matter of the dorsolateral fu-

niculi from the cervicomedullary junction extending contigu-

ously to the level of the sixth to seventh cervical intervertebral

disc (Figures 1A, B). In comparison with the unaffected areas of

brainstem, bilaterally symmetric intra-axial hyperintensities on

T2W images were noted in the pyramids (Figure 1C) and ventral

aspect of the crus cerebri of the brain. The lesions also were hy-

perintense on T2*W and T2W FLAIR images and were isointense

on T1W FLAIR images. Abnormal contrast enhancement was not

observed in the spinal cord and brain.

Cytology and protein analysis of cerebrospinal fluid obtained

from the cerebellomedullary cistern were normal. Based on the

signalment, history, the neurologic examination, and abnormal-

ities observed on MRI, a presumptive diagnosis of LEM was

made; however, infiltrative disease, such as neoplasia or infectious/

noninfectious inflammatory myelitis, could not be excluded.

Consequently, the dog was administered prednisonec (0.5 mg/kg

per os q 24 hr). After 10 days, no improvement was noted. Fifty

days after initial presentation, the dog was presented for humane

euthanasia. The owner stated that the dog could no longer walk

without falling down; however, if allowed to either run or walk

fast, the dog would not fall as often.

FIGURE 1 Transverse plane T2-weighted (T2W) MRI of the

second cervical vertebral (A) and fourth cervical vertebral (B) spinal

cord segments, the medulla oblongata (C) and corresponding gross

spinal cord specimen from the fourth cervical vertebra (D) from of

a 22 mo old male rottweiler with general proprioceptive ataxia and

upper motor neuron tetraparesis. There are bilaterally symmetrical,

hyperintense lesions in the dorsolateral funiculi of the spinal cord

(arrows in A and B). Images were acquired 50 days after initial

presentation. A, B: Insets are from the MRI performed on initial

presentation. In the caudal medulla oblongata, symmetrical hyper-

intensities also are observed in the pyramids of the medulla oblongata

(arrows in C). At the level of the fourth cervical vertebra, the

hyperintensities corresponded to bilaterally symmetric opaque foci

(arrows) on gross sections (D).

256 JAAHA | 49:4 Jul/Aug 2013

Prior to euthanasia and with owner consent, MRI of the

cervical vertebral column and brain was performed to determine if

the lesions had progressed. Imaging was performed as previously

described with the same unit, with the exception that the brain was

imaged with the dog in sternal recumbency using an extremity coil

to provide improved image quality. The previously identified

lesions were present, and new lesions were not identified. Sub-

jectively, the lesions in the white matter of the dorsal aspect of the

lateral funiculi were larger. The lesions in the brain were un-

changed in size. Following MRI, the dog was euthanized and

immediately necropsied.

At necropsy, gross lesions were restricted to the cervical

spinal cord and brainstem. Opaque white, well-demarcated, bi-

laterally symmetric foci were noted in the white matter in the

dorsal aspect of the lateral funiculi of the cervical spinal cord

(Figures 1D, 2A) and the pyramidal tracts of the medulla

oblongata. The crus cerebri were grossly normal. Brain, spinal

cord, and representative tissue samples of internal organs were

fixed in 10% neutral buffered formalin, processed, embedded in

paraffin, sectioned at 5mm, and stained with hematoxylin and

eosin. Selected sections of the brain and spinal cord were stained

with luxol fast blue.

Immunohistochemistry was performed with monoclonal

antibodies against neurofilamentd (1:8,0000), glial fibrillary acidic

proteine ([GFAP], 1:8,000), myelin basic proteinf ([MBP], 1:2,000),

and canine distemper virusg. Also samples from the affected

dorsolateral region of the lateral funiculus of the first cervical

spinal cord segment were removed at necropsy and fixed in 2%

(para)formaldehyde and 2% glutaraldehyde in 0.1 M phosphate

buffer for transmission electron microscopy. Following dehy-

dration in graded alcohols, the tissues were embedded in epon-

araldite. Thin sections were made and stained with lead citrate

and uranyl acetate.

On low power magnification, the white matter of the affected

areas observed onMRI showed amarked pallor consistent with loss

of myelin (Figures 2B, C). Microscopically, lesions were confined

to the white matter of the brain and spinal cord. The most severe

lesions were located in the cervical spinal cord, but lesions ex-

tended caudally into the thoracic spinal cord and rostrally into

the brainstem. Within the cervical spinal cord, the lesion affected

the white matter in the dorsal portion of the lateral funiculi in

the area of the dorsal spinocerebellar, lateral corticospinal, retic-

ulospinal, and rubrospinal tracts. A subpial rim of normal white

matter was always preserved except at the first cervical spinal cord

segment where the lesion extended to the pia. In the brain, the

pyramidal tracts, crus cerebri, area of medial lemniscus, caudal

cerebellar peduncle, trapezoid body, area of the spinal tract of the

trigeminal nerve, and area of the optic tracts were most severely

affected. The white matter of the cerebellar folia was also multi-

focally affected. The parenchymal portions of the oculomotor

nerves in the mesencephalon were mildly affected.

Within the affected white matter, myelin and axon loss was

observed. The myelin and axonal loss was replaced by promi-

nent astrogliosis and astrocytosis with numerous GFAP-positive

astrocytic processes and gemistocytic astrocytes in the affected

regions. Many normal appearing axons were present within the

area of severe demyelination. The degree of myelin loss exceeded

the loss of axons. Degenerative axonal changes were relatively mild,

FIGURE 2 Transverse gross and microscopic sections of the spi-

nal cord at the level of second cervical vertebra from the 22 mo old

male rottweiler in Figure 1 reveal lesions involving the white matter.

A: Similar to Figure 1D, gross transverse section of the cervical spinal

cord at the level of the second cervical vertebra, bilaterally symmetric

white foci are also evident in the dorsal area of the lateral funiculi

(arrows). B: On a low power magnification of a transverse section of

the cervical spinal cord, there are bilaterally symmetric areas of pallor

in the lateral funiculi (arrows). Hematoxylin and eosin staining,

bar ¼ 2 mm. Inset of B: A transverse section of the cervical spinal

cord from banked tissue from an age matched control dog. Bar ¼2 mm. Note the uniform staining of the white matter. C: The bi-

laterally symmetric areas of pallor in the dorsal areas of the lateral

funiculi indicate loss of myelin (arrows). Luxol fast blue staining,

bar ¼ 2 mm. Inset of C: A transverse section of the cervical spinal

cord from banked tissue from an age matched control dog. Note the

uniform staining of the white matter. Bar ¼ 2mm. D: The loss of

myelin is replaced by gliosis with numerous gemistocytic astrocytes

(arrows). In the affected areas, vessels are prominent with hyper-

trophy of the endothelial cells (arrowheads). Hematoxylin and eosin

staining, original magnification 3400, bar ¼ 40 mm.

MRI Findings in a Rottweiler with Leukoencephalomyelopathy

JAAHA.ORG 257

digestion chambers were rare, and few axonal spheroids were seen.

In affected areas, vessels were mildly thickened with prominent

endothelial cells and increased cellularity of the perivascular space

(Figure 2D).

To better assess myelin content and axonal changes, banked

tissue samples of the cervical spinal cord from an age matched

control dog free of neurologic disease were used for comparison. In

the affected dog, immunohistochemistry for MBP confirmed

partial to total loss of myelin in the white matter of affected areas

with patchy staining of the remaining white matter and naked

axons compared to the control dog. (Figures 3A, B) Immuno-

histochemistry for neurofilament demonstrated decreased num-

bers of axons. (Figures 3C, D) Multiple axons had irregular

profiles and many were smaller. Only a few axons were larger than

in the control dog. In the affected dog, immunohistochemistry for

GFAP revealed the abnormal neuroparenchyma to consist mostly of

gemistocytic astrocytes as well as astrocytic processes (Figures 3E, F)

Immunohistochemistry for canine distemper virus was negative.

Ultrastructurally, affected spinal cord white matter contained

oligodendroglia, a small number of small naked axons, small

numbers of myelinated axons, and hypertrophied astrocytic

processes (Figure 4A). Myelinated axons were some of the larger

axons present and were typically irregularly shaped. The myelin

sheaths had extensive splitting of the lamellae and lack of

compaction. Schwann cells with similarly myelinated axons

were present near vessels indicating Schwann cell remyelination

(Figure 4B).

DiscussionThe clinical and pathologic features of the dog described in this

report are consistent with a diagnosis of LEM as previously de-

scribed in rottweilers.1,3 A definitive diagnosis of LEM requires

histopathology. In this case, MRI precisely identified the affected

areas, allowing representative transverse sections to be obtained

for macroscopic, histopathologic, and ultrastructural examina-

tion. In the case reported here, bilaterally symmetric, continuous

hyperintensities on T2W images were identified in the same to-

pography as reported for the most severe lesions in LEM in

rottweilers.1–3 Moreover, the lesions observed on MRI in the

present case correlated with the degenerative changes in the white

matter observed histologically, which included severe loss of

myelin and astrogliosis. Those findings were similar to findings

FIGURE 3 Microscopic sections of the demyelinated area of dorsolateral lateral funiculus of the first cervical vertebral spinal cord segment

from the affected rottweiler compared with the white matter of a similar area of the cervical spinal cord from banked tissue samples from an

age matched control dog free of neurologic disease using a variety of immunohistochemical stains. A: Immunohistochemical stain for myelin

basic protein (MBP). In the bilaterally symmetric areas of pallor in the cervical spinal cord, there is severe myelin loss around axons with

minimal punctuate positive remnants of myelin. MPB with fast red chromogen/hematoxylin counterstain, original magnification 31000.

B: For comparison, similar location of the cervical spinal cord from a normal dog stained for MBP with fast red chromogen/hematoxylin

counterstain, original magnification 31000. C: Immunohistochemical stain for neurofilament reveals decreased axon numbers. Di-

aminobenzidine (DAB) chromogen/hematoxylin counterstain, original magnification 31000. D: For comparison, similar location of the cervical

spinal cord from a normal dog stained for neurofilament as in panel C, original magnification 31000. E: Immunohistochemical stain for glial

fibrillary acidic protein (GFAP). Myelin loss is replaced by astrocytosis and gemistocytic astrocytes. DAB chromagen/hematoxylin counterstain,

original magnification 31000. F: For comparison, similar location of the cervical spinal cord from a normal dog stained for glial fibrillary acidic

protein (GFAP) as in panel E. DAB chromagen/hematoxylin counterstain, original magnification 31000. Bar ¼ 15 mm.

258 JAAHA | 49:4 Jul/Aug 2013

previously described in rottweilers.3 Further, microscopic inves-

tigation in the present case using immunohistochemistry (i.e.,

antibodies against MBP, neurofilament, and GFAP) and electron

microscopy corroborated severe myelin loss, astrogliosis/astrocytosis,

as well as demonstrating decreased numbers and degeneration of

axons. In addition, minimal abortive attempts of oligodendroglial

and Schwann cell remyelination were present ultrastructurally. In-

terestingly, Schwann cells have not be observed in the spinal cord in

previously reported cases of LEM.1 Schwann cell invasion into the

spinal cord can occur in a variety of conditions, including primary

myelin disorders as well as focal compressive and concussive pro-

cesses.4 Although typically excluded from the CNS, Schwann cell

invasion occurs at transition zones where the peripheral nervous

system interfaces with the CNS, such as the dorsal and ventral root

entry zones and near blood vessels.5 Consistent with this,

Schwann cells in the present case were observed near blood vessels.

Given the MRI characteristics and topography of the lesions

observed in the dog reported here, many of the differential

diagnoses for clinical signs referable to the first through fifth

cervical spinal cord segments can be eliminated from consider-

ation. Other important degenerative nervous system disorders may

affect rottweilers. Those degenerative diseases must be considered

in the differential diagnoses. NAD is a neurodegenerative disease

that presents in young rottweilers as a chronic, progressive, general

proprioceptive ataxia and upper motor neuron paresis of all four

limbs.6,7 Pathologically, NAD results in axonal swellings (spher-

oids) throughout the CNS gray matter, except the cerebral cor-

tex.6 The spheroids are primarily localized in the distal regions

and axon terminals of afferent fibers entering sensory nuclei in

the spinal cord, brainstem, and diencephalon.6 Cerebellar atrophy

may also be appreciated in more chronic cases.6,7 Although not

described in rottweilers with NAD, the MRI findings have been

documented in one papillon with NAD.8 At 3 mo of age, no ab-

normalities were detected; however, at 6 mo of age, diffuse atrophy

of the cerebrum, cerebellum, and brainstem were seen in the af-

fected dog.8 In humans with NAD, the most consistent MRI ab-

normality observed is a hyperintense cerebellum on T2W and T2

FLAIR images.9 To the authors’ knowledge, reports detailing im-

aging studies involving encephalomyelopathy and polyneuropathy

in the rottweiler have not been published. Of the available MRI data

for LEM and NAD in the dog, no similarities are seen. Encepha-

lomyelopathy and polyneuropathy has also been reported in young

rottweilers.10 Signs consist of ataxia and paresis involving all four

limbs as well as laryngeal and pharyngeal dysfunction.10 Although

initial signs share similarities with LEM, dogs with encephalo-

myelopathy and polyneuropathy are typically younger and, with

disease progression, signs reflect neuromuscular dysfunction.10

MRI has been used in other white matter disorders. In spongy

degeneration of the CNS in Labrador retrievers, MRI disclosed

symmetrical, hyperintense lesions on T2W images, which cor-

related with degenerative white matter lesions detected during

gross and histologic examination.11 Recently, a novel LEM in two

leonbergers was described.12 As in the present case, the bilaterally

symmetric hyperintensities on T2W images were observed in the

dorsolateral funiculi of the spinal cord; however, lesions were

restricted to the second cervical spinal cord segment in one dog

and to the second to fourth cervical spinal cord segments in the

other dog. Additionally, lesions were not noted on MRI of the

brain in affected leonbergers. MRI of globoid cell leukodystrophy

of the West Highland white terrier revealed bilaterally sym-

metrical, hyperintense lesions on T2W images, which included

the corpus callosum, centrum semiovale, internal capsule, co-

rona radiate, and cerebellar white matter. Symmetrical contrast

enhancement was observed in the corpus callosum, internal

capsule, and corona radiata on T1W postcontrast images.13

FIGURE 4 Electron micrographs from a demyelinated area of

dorsolateral lateral funiculus of the first cervical vertebral spinal cord

segment reveal axons that are few in number and scattered among

oligodendroglial processes. A: Those axons present are irregularly

shaped (A) with wavy decompacted myelin sheaths (M). Lead cit-

rate/uranyl acetate staining, bar ¼ 1 mm. B: Schwann cell remye-

lination is evident. Myelinated axons (A) are observed surrounded

by Schwann cells (S) with basement membrane (arrow). Note the

wavy, decompacted myelin (M) and adjacent hypertrophied astro-

cytic process (As). Lead citrate/uranyl acetate staining, bar ¼ 1 mm.


JAAHA.ORG 259

Demyelinating lesions have been found to correlate well with areas

of hyperintensity on T2W images in canine distemper.14 Dysmye-

linogenesis in the English springer spaniel and Portuguese water

dog secondary to GM1 gangliosidosis was correlated with a mild

hyperintensity of the corona radiata on T2W images.15

The etiology of LEM remains obscure, and the pathogenesis

still remains to be determined. Bilaterally symmetric degenerative

lesions in the CNS are usually due to nutritional, metabolic, or

toxic causes.16,17 It is possible that LEM is a result of an inborn error

of metabolism.3 In humans, numerous primary disorders of myelin

occur secondary to inborn errors of metabolism.18 In two dogs with

LEM, biochemical analysis of peripheral blood leukocytes for evi-

dence of lysosomal storage defects was evaluated for activity of

b-galactosidase, b-hexosaminidase, b-hexosaminidase A, aryl sul-

phatase A, acid phosphatase, b-glucuronidase, a-mannosidase,

a-fucosidase, b-glucocerebrosidase, b-galactocerebrosidase, and

sphingomyelinase). All evaluations were normal.2

Based on immunohistochemical and ultrastructural studies in

those cases, the lesions are clearly demyelinating with simulta-

neous, although inadequate and abnormal, remyelination. The

question remains whether the defect in LEM involves either

a primary disorder of oligodendrocytes (primary demyelination)

or loss of myelin secondary to primary changes in the axons

(axonopathy). Oevermann et al. (2008) hypothesized that LEM in

the leonberger was a consequence of an alteration in the intimate

relationship between the oligodendrocyte and the neuron so

myelin was produced, but not stable, and the topography of the

lesion reflected the population of neurons affected.12 In humans,

there is a close relation between myelin and axon, where axonal

pathology may precede demyelination.19–21 Interestingly, in this

case, not only was myelin loss observed, but also decreased axonal

diameters and irregularity in axonal shape. That finding could be

related to either loss or disorganization of the neurofilaments, and

thus, impaired cytoskeletal organization and axonal transport in

dogs with LEM. Minimal attempts at remyelination were seen in

this case, some of which was due to Schwann cells migrating into the

spinal cord, suggesting disruption of the glia limitans formed

by astroglia, which, as a consequence of disruption, allowed

Schwann cells to enter the CNS and promote remyelination.22 That

could indicate that the Schwann cells were compensating for some

form of oligodendrocyte/neuronal dysfunction that caused demye-

lination; however, there was also evidence of remyelination by oli-

godendroglia, albeit abnormal. Although speculative, given the more

severe pathologic involvement of myelin than axons observed his-

tologically and ultrastructurally in the case reported herein, the

underlying disease process likely represents a leukodystrophy

rather than an axonal disorder with secondary demyelination.

In the present case, MRI was helpful in establishing a pre-

sumptive antemortem diagnosis of LEM. Although unknown, it is

possible that either early in the course of the disease or if clinical

signs are mild, lesions may not be detected with MRI. The factors

that contribute to lesion conspicuity likely include the degree

of myelin loss, number of affected axons (and their diameter),

and number of glial cells in the white matter. Additionally, the

sophistication of the MRI unit also may play a role. In the present

case, the lesions in the white matter of the dorsal aspect of the

lateral funiculi were larger after 50 days. Therefore, a repeat MRI

should be recommended in cases where there is a high index of

suspicion yet lesions are not observed.

ConclusionUnderstanding the correlation between lesion characteristics and

topography on MRI and histologic findings can refine the diag-

nostic approach categorizing different morphologic changes ob-

served in the CNS. The ability to establish an accurate presumptive

antemortem diagnosis of LEM has many implications. Although

not established, given the occurrence of LEM in a specific breed,

the rottweiler, a hereditary basis is suspected. The ability to identify

affected individuals and remove them from the breeding pool is

imperative. Also, owners of affected dogs could be provided an

accurate prognosis as rottweilers with LEM are typically euthanized

within 1 yr of diagnosis.

FOOTNOTESa Signa HDx; GE Healthcare, Milwaukee, WIb Magnevist; Berlex Laboratories, Wayne, NJc Prednisone; West-Ward Pharmaceutical Corp., Eatontown, NJd Neurofilament antibody; Biogenex, San Ramon, CAe Glial fibrillary acidic protein antibody; Abcam, Cambridge, MAf Myelin basic protein antibody; Abcam, Cambridge, MAg Canine distemper virus antibody; VMDR, Pullman WA

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CASE REPORT Open Access

Magnetic resonance imaging and geneticinvestigation of a case of rottweilerleukoencephalomyelopathyKatrin Hirschvogel1, Kaspar Matiasek2, Katharina Flatz3, Michaela Drögemüller4, Cord Drögemüller4, Bärbel Reiner2

and Andrea Fischer1*

Abstract

Background: Leukoencephalomyelopathy is an inherited neurodegenerative disorder that affects the white matterof the spinal cord and brain and is known to occur in the Rottweiler breed. Due to the lack of a genetic test forthis disorder, post mortem neuropathological examinations are required to confirm the diagnosis.Leukoencephalopathy with brain stem and spinal cord involvement and elevated lactate levels is a rare, autosomalrecessive disorder in humans that was recently described to have clinical features and magnetic resonance imaging(MRI) findings that are similar to the histopathologic lesions that define leukoencephalomyelopathy in Rottweilers.Leukoencephalopathy with brain stem and spinal cord involvement is caused by mutations in the DARS2 gene,which encodes a mitochondrial aspartyl-tRNA synthetase. The objective of this case report is to present the resultsof MRI and candidate gene analysis of a case of Rottweiler leukoencephalomyelopathy to investigate thehypothesis that leukoencephalomyelopathy in Rottweilers could serve as an animal model of humanleukoencephalopathy with brain stem and spinal cord involvement.

Case presentation: A two-and-a-half-year-old male purebred Rottweiler was evaluated for generalised progressiveataxia with hypermetria that was most evident in the thoracic limbs. MRI (T2-weighted) demonstrated well-circumscribed hyperintense signals within both lateral funiculi that extended from the level of the first to the sixthcervical vertebral body. A neurodegenerative disorder was suspected based on the progressive clinical course andMRI findings, and Rottweiler leukoencephalomyelopathy was subsequently confirmed via histopathology. TheDARS2 gene was investigated as a causative candidate, but a sequence analysis failed to identify any disease-associated variants in the DNA sequence.

Conclusion: It was concluded that MRI may aid in the pre-mortem diagnosis of suspected cases ofleukoencephalomyelopathy. Genes other than DARS2 may be involved in Rottweiler leukoencephalomyelopathyand may also be relevant in human leukoencephalopathy with brain stem and spinal cord involvement.

Keywords: Rottweiler, DARS2, LBSL, White matter disease, Progressive ataxia

* Correspondence: [email protected] of Veterinary Clinical Sciences Ludwig-Maximilians-Universitaet,Neurology Service, Clinic of Small Animal Medicine, Munich, GermanyFull list of author information is available at the end of the article

© 2013 Hirschvogel et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of theCreative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use,distribution, and reproduction in any medium, provided the original work is properly cited.

Hirschvogel et al. BMC Veterinary Research 2013, 9:57http://www.biomedcentral.com/1746-6148/9/57

BackgroundRottweiler leukoencephalomyelopathy (LEM) was initiallyrecognised in the US as a cause of chronic progressiveataxia with insidious onset in Rottweilers between 1.5 and4 years of age [1]. The clinical and pathological character-istics of this disease entity were further defined in subse-quent reports originating from Australia, the Netherlandsand the UK, which described 16 pathologically confirmedcases (of 22 total cases described in the literature) andsuggested an autosomal recessive pattern of inheritance[2-6]. In these reports, Rottweiler LEM presented as a dis-tinctive neurodegenerative disorder restricted to the lat-eral and dorsal funiculi of the cervical spinal cord andspinal tracts of the trigeminal nerve, pyramids, caudalcerebellar peduncles, cerebellar medulla and optic tractsthat showed a sharp demarcation between abnormal andnormal white matter and occasional microcavitation inthe centre of the lesion. Clinically, affected dogs exhibitprogressive ataxia with hypermetria and subtle posturalreaction deficits. Thus far, the ante mortem diagnosis ofLEM in Rottweilers has been based on clinical suspicionand the exclusion of other diseases of the cervical spinalcord, e.g., compression/instability, neoplasia and inflam-mation. To date, there have been no magnetic resonanceimaging (MRI) studies or genetic investigations of this dis-ease entity.Leukoencephalopathy with brain stem and spinal cord

involvement and lactate elevation (LBSL) is a neurodegen-erative disease in humans with clinical features and MRIfindings that are surprisingly similar to the histopathologiclesions of LEM in Rottweilers. Specifically, these patientsexhibit slow progressive spasticity and ataxia, MRI find-ings of selective involvement of the brain stem and spinaltracts in both lateral funiculi and dorsal columns andchanges in the cerebral and cerebellar white matter. Spinalcord involvement with MR signal intensity changes hasalso been reported in other leukodystrophies in humans,e.g., adult onset autosomal dominant leukodystrophy withautonomic features, Alexander’s disease, vitamin B12 defi-ciency myelopathy and sporadic cases of adult onset lyso-somal leukodystrophies [7-11]; however, a very distinctand well-demarcated pattern of signal intensity change isconsidered to be most characteristic of LBSL. In LBSL,high levels of lactate are frequently demonstrated in brainlesions using magnetic resonance (MR) spectroscopy; thisfinding suggests a respiratory chain defect, but lactate israrely elevated in the blood or cerebrospinal fluid (CSF)[12,13]. To date, all human cases of LBSL have been foundto be caused by mutations in the DARS2 gene, which en-codes mitochondrial aspartyl-tRNA synthetase [14,15].To investigate the hypothesis that LEM in Rottweilers

could represent a possible animal model of LBSL, MRIresults and DARS2 gene integrity were investigated in asingle, affected dog.

Case presentationA two-and-a-half-year-old male purebred Rottweiler wasreferred for further investigation of progressive ataxia. Thedog had been placed in an animal shelter 8 weeks prior tothe study. Unfortunately, no pedigree data were available,and we were unable to ascertain whether inbreeding hadoccurred. At the time of shelter placement, the dog hadalready been ataxic, and the ataxia progressed during thesubsequent 8 weeks. Haematologic and serum biochem-ical analyses, thoracic and abdominal radiographs, andechocardiography had been performed prior to referral,and the findings were unremarkable.Physical examination showed excessive wearing of the

nails on all four limbs, particularly of the thoracic limbs.A neurological examination showed severe generalisedataxia with hypermetria of the thoracic (prolonged pro-traction and overreaching action with limb extension)and pelvic limbs. Additionally, difficulties in rising, inter-mittent crossing of the thoracic limbs, and a wide-basedstance of all limbs were observed. The postural reactions(wheelbarrowing with and without neck extension, hop-ping, and proprioceptive positioning) were delayed, andthe thoracic limbs were more severely affected than thepelvic limbs. A supplemental movie file shows thesefindings in more detail (see Additional file 1). The spinalreflexes (extensor carpi radialis, thoracic and pelvic limbflexor, patellar, cranial tibial, gastrocnemius, cutaneoustrunci, and perineal) were all normal. The mentationand cranial nerve function, including vision, were unim-paired, but an inconsistent menace response was ob-served; this was attributed to the lack of cooperation bythe dog but could also indicate a cerebellar lesion. Palpa-tion of the head and spine and neck flexion and exten-sion did not elicit any signs of pain. There was noevidence of tremor or uncoordinated movements of thehead. The findings of the neurological examination weremost consistent with a cervical myelopathy (C1-C5spinal cord segments) involving the spinocerebellartracts, although a cerebellar lesion could not be ruledout completely. The differential diagnoses included severalbreed-related neurodegenerative disorders: neuronal vacu-olation and spinocerebellar degeneration, neuroaxonal dys-trophy, LEM, cervical spondylomyelopathy and arachnoiddiverticula [16-20].A follow-up laboratory examination revealed mild eo-

sinophilia (1.51 × 103 eosinophilic granulocytes/μl; referencerange: 0.04 - 0.6 × 103/μl) and unremarkable serum bio-chemical results. The dog was subsequently anesthetisedfor further examination of the cervical spine and brainusing MRI and CSF analysis. Electrodiagnostic examinationwas scheduled as a supplemental examination to investigatethe presence of additional lesions in the peripheral nerves.Magnetic resonance imaging was performed using a 1.5 Tmagnetic resonance unit. The brain imaging protocol

Hirschvogel et al. BMC Veterinary Research 2013, 9:57 Page 2 of 8http://www.biomedcentral.com/1746-6148/9/57

utilised sagittal, dorsal and transverse T2-weighted (TR/TE5190/108 ms) and T1-weighted (TR/TE 386/13 ms) se-quences and transverse FLAIR (TR/TE/TI 9110/122/2500 ms) and gradient echo (TR/TE 1000/28 ms) se-quences. The spinal imaging protocol included sagittal anddorsal T2-weighted (TR/TE 2880/111 ms) and T1-weighted (TR/TE 623/1 ms), transverse T2-weighted (TR/TE 3290/99 ms) and T1-weighted (TR/TE 651/12 ms) andsagittal STIR (TR/TE/TI 3310/61/140 ms) sequences. Thesagittal and dorsal spinal sequences were performed fromC1 to T3 (vertebral body), and the transverse sequencesused C1 to C7 (vertebral body). Gadolinium (0.1 mmol/kg;0.045 mmol/lb) was administered intravenously, and post-contrast transverse T1-weighted sequences of the brain anddorsal and sagittal T1-weighted sequences of the spine wereacquired. Descriptions of intensity referred to normal ap-pearance of grey matter. The spinal MRI studies showed bi-lateral symmetrical hyperintensities in the region of bothlateral funiculi on transverse T2-weighted images (Figure 1).The lesions were most visible on the transverse sections;they appeared well demarcated and ovoid and extendedfrom the level of the first to the sixth cervical vertebral body(Figure 2). In T1-weighted plain images, the lesions wereisointense, and no contrast enhancement was observed.MRI studies of the brain failed to reveal any abnormalities.Routine CSF analysis (cisterna cerebellomedullaris)

with leukocyte (0/μl; reference range 0- 5/μl) anderythrocyte counts (4/μl), CSF cytology and protein mea-surements (0.18 g/l; reference range 0–0.3 g/l) were un-remarkable, as were the lactate concentrations in theCSF (1.6 mmol/l; reference range 0.2-3.1 mmol/l[21,22]) and serum (1.0 mmol/l; reference range 1.1-

Figure 1 Transverse T2-weighted MR images of the cervicalspinal cord at the level of the C4-C5 intervertebral disc space.The images show well-demarcated, ovoid, hyperintense signals witha bilateral, symmetrical appearance in the region of the lateralfuniculi (arrow).

Figure 2 Dorsal T2-weighted MR images of the cervical spinalcord. The image shows linear, hyperintense signals (arrow)corresponding to the lesions in Figure 1 that extend from the levelof the first to the sixth cervical vertebral body in a bilateral,symmetrical fashion. The line denotes the C4-C5 intervertebraldisk space.


3.3 mmol/l [22]). No abnormal spontaneous activity pat-tern was observed during electromyographic recordingsusing a concentric needle electrode in the anesthetiseddog. The tibial and ulnar motor nerve conduction vel-ocity, tibial nerve F-waves and repetitive nerve stimula-tion were within established laboratory reference ranges.Considering the progressive clinical course and the

MRI lesion pattern, a neurodegenerative disorder pre-dominantly involving the cervical spinal cord white mat-ter with a bilateral and symmetrical distribution wassuspected. Due to the existing severe neurological signs,the progressive deterioration and the poor prognosis, thedog was euthanised.A complete necropsy was performed, and it confirmed

Rottweiler LEM. Significant lesions were confined to thecentral nervous system. Macroscopic examination revealedbilateral, symmetrical lesions restricted to the dorsal aspectof the lateral funiculi of the cervical spinal cord segments.In transverse sections, these lesions appeared as well-demarcated, whitish, opaque discoloured areas (Figure 3).No gross changes were observed in the brain. Formalin-fixed and paraffin-embedded tissue samples of the brainand spinal cord were sectioned at 5 μm and stained usinghaematoxylin-eosin and Luxol Fast Blue for histological

examination. Histologically, the cervical spinal cord (fromC2 to C6 (vertebral body)) exhibited severe, bilaterally sym-metrical funicular disruption of the inner dorsal part of thelateral funiculus, including the rubrospinal tract, the inner-most layer of the dorsal spinocerebellar tract and the dorsalaspects of the lateral fasciculus proprius. Upon low-powerinspection, the lesion was characterised by a severe loss ofmyelin staining; at high-power, the lesion resembled adense core of non-myelinated white matter with extensiveastrocytosis and astrogliosis with the occasional observa-tion of bizarre cells surrounded by a rim of spongioticwhite matter with fibre degeneration, resorptive lesions,vascular prominence and mild-to-marked angiocentriclymphohistiocytic infiltration. The adjacent cervical greymatter appeared hypoplastic in both the ventral and dorsalhorns, but there were no further histomorphologicalchanges. Another severe white matter lesion identified inthe cerebellar roof showed focal, bilaterally symmetric tis-sue necrosis, macrospongiosis due to interlamellar myelinsheath oedema (ballooning) and severe intralesionalastrogliosis and astrocytosis accompanied by fibrillaryastrogliosis and gemistocytes at the margins. A moderatevascular prominence with endothelial hyperplasia wasagain observed both in the intra- and perilesional areas.

Figure 3 Pathological lesions in the brain (A, B) & spinal cord (C, D). The most severe white matter lesions were observed in the cerebellum(A: asterisk) and cervical spinal cord (C: framed area). Macroscopic examination revealed bilateral, symmetrical lesions in the lateral funiculi of thecervical cord segments only. In transverse sections, these lesions appeared as well-demarcated, whitish, opaque discoloured areas (C: framedarea). The cerebellar lesions spared the fibres adjacent to the roof nuclei (A: arrow). Nuclear degeneration was most severe in the raphe nuclei (B)and medial vestibular nuclei (not shown). Note the extensive juxtaneuronal vacuolisation (B: asterisk). The affected spinal cord segments showdemyelination, astrogliosis and astrocytosis (D: white arrowhead) with gemistocytes (D: black arrowheads). Within the grey matter, hypoplasia ofthe dorsal and ventral horn (C: black arrow) is evident. Scale bars: A: 1.5 cm; B: 100 μm; C: 2 mm; D: 35 μm.


Necrotic areas exhibited macrophage-mediated resorption(Figure 3).Similar demyelinating lesions were observed in the pyra-

mids and caudal cerebellar peduncles and – to a lesserextent – in the medial lemniscus, optic tracts, cruracerebri and subcortical white matter. Lesions in the cen-tral visual pathways projected to the optic nerves andmanifested as the degeneration of multiple fibres. Furtherbrain stem changes included macrovacuolar degenerationof the raphe nuclei and medial vestibular nuclei associatedwith mild gliosis and axonal spheroids. Immunohisto-chemical staining for canine distemper virus was negative.A mild diffuse endoneurial hypercellularity was observedin the preganglionic aspects of the dorsal roots of the cer-vical spine. Both the radial and common peroneal nervepresented with a mild dropout of myelinated fibres, as de-noted by enlarged subperineurial spaces with myxoid re-placement oedema, reduced endoneurial area anddecreased myelinated nerve fibre density that was associ-ated with a mild expansion of the endoneurial collagenousmatrix. Residual large A (alpha)-type myelinated fibresshowed myelin ovoids, consistent with stage II – IIIWallerian degeneration, and abundant internodal andparanodal inner and outer myelin loops due to the moder-ate axonal atrophy of the respective fibres.Due to the phenotypic similarities between human

LBSL patients and LEM-affected Rottweilers, the DARS2gene was investigated as a candidate for canine LEM.Genomic DNA was extracted from blood collected intubes containing EDTA using DNeasy blood spin col-umns (Qiagen). For the DARS2 mutation analysis, suit-able PCR products were amplified using AmpliTaq Gold360 (Life Technologies). The PCR products wereresequenced after rAPid alkaline phosphatase (Roche)and exonuclease I (New England Biolabs) treatmentusing both PCR primers and the ABI BigDye TerminatorSequencing Kit 3.1 (Life Technologies) in an ABI 3730sequencer (see Additional file 2: Table S1). The sequencedata were analysed using Sequencer 4.9 software(GeneCodes). The sequences of all 17 coding exons andflanking intron sequences of the DARS2 gene from theaffected Rottweiler were identical to a canine referencegenome sequence (CanFam3 assembly; http://genome.ucsc.edu).

ConclusionMagnetic resonance imaging has become the primarytool for the ante mortem diagnosis of white matter dis-ease in humans due to its high sensitivity for detectingchanges in white matter. Decreased myelin and elevatedwater content is revealed by increased T1 and T2 relax-ation times, with a consequent reduction in signal inten-sity in T1-weighted images and increased signal intensityin T2-weighted images [23]. Thus, the pattern of MRI

changes is very helpful in defining disease because it re-veals the distribution of histopathologic changes [24,25].At present, there are few case reports describing the use

of MRI for the diagnosis of canine and feline neurodegen-erative diseases. T2-weighted hyperintensities of whitebrain matter were evident in cats with GM2 gangliosidosis[26,27] and in a West Highland white terrier with globoidcell leukodystrophy [28]. Increased signal was also evidentin T2-weighted images of the spinal cord of Leonbergerdogs with leukoencephalomyelopathy [29]. Dogs withGM2 gangliosidosis displayed T2-weighted hyperintensitiesin the region of the caudate nucleus and atrophy of thecerebrum and cerebellum [30,31]. MRI of Papillon dogswith neuroaxonal dystrophy [32] and Scottish Terriers withhereditary cerebellar degeneration demonstrated atrophyonly and failed to detect changes in white matter [33].MRI of the cervical spine may be used to support the

clinical diagnosis of LEM in Rottweilers. A similar MRIpattern has been described in Leonberger dogs withLEM [29]. Interestingly, however, brain lesions were notdetected using MRI in the Leonberger dogs or in thecase reported here, although histological analysesshowed that the optic tracts and particularly the cerebel-lar medulla were significantly affected in both breeds[2,29]. It is possible that the white matter lesions in thebrain were less advanced than those in the spinal cord atthe time of imaging, and improved imaging protocolsmay be required for the visualisation of brain lesions.These protocols may include smaller slice thicknessesand the application of sequences other than conven-tional T1- and T2-weighted imaging, e.g., diffusion ten-sor imaging, magnetisation transfer imaging or MRspectroscopy [34]. It is also questionable whether thepathological changes in these regions have sufficiently al-tered the physics of the tissue to induce changes visiblewith a 1.5 T clinical scanner.Many inherited white matter diseases and associated

genetic defects have been described in humans [35].Leukoencephalopathies may be characterised as lysosomalor peroxisomal disorders, mitochondrial disorders, methy-lation cycle disorders, organic acidaemias or amino aciddisorders or as leukoencephalopathy associated with calci-fication, hypomyelination, abnormal lipid metabolism,vasculopathy or muscular dystrophy. Many distinct en-tities, e.g., Alexander’s disease, adult onset autosomal dom-inant leukoencephalopathy, vanishing white matter diseaseand adult polyglucosan encephalopathy, have also beenrecognised. A vast number of genetic defects are currentlyassociated with these conditions, and many more remainto be elucidated; the molecular cause remains unknownin ~50% of affected humans [35]. The lesion distributionand MRI appearance of LBSL are considered unique anddiagnostic in humans; consequently, only a single candi-date gene was examined in the present study [36].


Leukoencephalopathy with brain stem and spinal cordinvolvement is a rare, autosomal recessive disorder thattypically manifests in childhood or adolescence. Thediagnosis of LBSL in humans is based on clinical presen-tation and is characterised by a slowly progressive cere-bellar ataxia, spasticity, dorsal column dysfunction and ahighly characteristic pattern of abnormalities observedusing MRI and spectroscopy. Typical MRI findings in-clude a combination of high T2-weighted signal changesin the cerebral white matter accompanied by the select-ive involvement of the brain stem and spinal cord tracts(the entire length of the pyramidal tracts with the add-itional involvement of cerebellar connections and theintraparenchymal and mesencephalic parts of the tri-geminal nerve) [13,37]. MR spectroscopy demonstratesan elevation in lactate levels in the abnormal white mat-ter of almost all of the affected human patients. Thesefindings led researchers to assume that the disease was amitochondrial disorder, which was subsequently con-firmed by the discovery of various mutations in theDARS2 gene, which encodes mitochondrial aspartyl-tRNA synthetase [14,38]. As demonstrated by multiplecase reports of LBSL in humans, normal CSF and bloodlactate concentrations, as were noted in the casereported herein, do not exclude a mitochondrial disorderas the underlying cause of leukoencephalomyelopathy.Thus, further investigations should utilise MR spectros-copy to investigate the possible mitochondrial origin ofRottweiler LEM.The diagnosis of mitochondrial disorders faces spe-

cific difficulties due to the complex genetics of theseconditions. Mitochondrial disorders may occur due tomutations in mitochondrial genes or mutations in nu-clear proteins, with mitochondrial tRNA representing ahot spot for mutations. Heteroplasmy, i.e., the simul-taneous presence of mutated and normal RNA/DNA inthe cell, is a characteristic feature of mitochondrial dis-orders. The degree of heteroplasmy varies between tis-sues in the same organism, which is considered acritical factor in the manifestation of mitochondrial dis-ease in specific tissues [36,39]. Finally, we investigatedthe coding region of the canine DARS2 gene as a candi-date causative gene for LEM, and no mutation wasfound. At this time, we cannot rule out the possibilityof variants in the promoter or intronic regions thatcould affect DARS2 expression. More comprehensiveDNA sequencing approaches, such as the use of next-generation technologies for whole-exome or whole-genome resequencing, may enable the identification ofthe causative mutation of Rottweiler LEM. A recentstudy identified the causative mutation of canine neo-natal cerebellar cortical degeneration in SPTBN2 (gen-ome-wide mRNA sequencing) using only a single caseof this neurodegenerative disease [40].

Further limitations of our case report include the lackof pedigree analysis and brain lactate MR spectroscopymeasurements and the failure of MR to demonstrate theinvolvement of the cerebrum despite the pathology ob-served in histological sections. Another limitation is thatthe comparison of the pathologies of these diseases indogs and humans is limited by the paucity of case datafrom both. To date, there is only one short descriptionof the pathology of LBSL in humans which has shownspongy white matter degeneration, rarefaction of theneuropil, macrophage infiltration and an increased num-ber of astrocytes in the white matter of the brain andaxonal degeneration of the peripheral nerves [25]. Spinalcord changes have not been noted, but it is unknownwhether this part of the CNS was sampled and investi-gated. In dogs with LBSL-like changes, the neuroana-tomical mapping of CNS lesions is more precise [2,29].Clinical and pathological findings emphasise cerebellarand spinal changes, although the microscopic white mat-ter damage is far more widespread and extends from thelower brain stem to the subcortical white matter. Con-sistent with the fibres affected, Gamble et al. discoveredsecondary grey matter changes in connected brain stemnuclei, such as the accessory cuneate nucleus, nucleusgracilis, nucleus cuneatus and nucleus of the dorsalspinocerebellar tract [1]. However, the involvement ofmultiple independent centres and tracts is compatiblewith multisystemic degeneration, as has been shown inLeonbergers and Rottweilers (discussed above) [2,29].We also discovered macrovacuolar nuclear degenerationin the Rottweiler, which has not previously been de-scribed in dogs. Vacuole formation in LBSL patients waspredominantly perineuronal and was therefore dissimilarto the neuronal vacuolation and spinocerebellar degener-ation observed in Rottweiler dogs [16]. This degener-ation merits further examination to investigate therelationship between neurons and astrocytes in the sub-cortical grey matter. It also remains to be establishedwhether this manifestation causes the white matter path-ology or whether it is an additional, co-existing disorderthat is distinct from the breed-specific neurodegenera-tive disorders described above.In summary, magnetic resonance imaging revealed

leukodystrophic lesions in the lateral funiculi of the cer-vical spinal cord; these findings will assist in the antemortem diagnosis of future cases of suspected LEM inRottweilers. Further investigations should utilise MRspectroscopy to investigate the possible mitochondrialorigin of Rottweiler LEM. Although LEM is similar toLBSL based on its clinical features and imaging results,we were unable to identify a coding or splice site muta-tion in the canine DARS2 gene in our case, suggestingthat other genes may be involved in Rottweiler LEM andpotentially also in human LBSL.


Additional files

Additional file 1: Movie of a Rottweiler with confirmedleukoencephalomyelopathy. The movie shows the severe generalisedataxia with hypermetria of the thoracic (with prolonged protraction,overreaching action and limb extension) and pelvic limbs. The posturalreactions were delayed, and the thoracic limbs were more severelyaffected than the pelvic limbs.

Additional file 2: Sequencing methods and primers.

AbbreviationsCSF: Cerebrospinal Fluid; FLAIR: Fluid-Attenuated Inversion Recovery;LBSL: Leukoencephalopathy with Brain Stem and Spinal Cord Involvement;LEM: Leukoencephalomyelopathy; MR: Magnetic Resonance; MRI: MagneticResonance Imaging; Ms: Millisecond; TE: Time to Echo; TR: Time toRepetition.

Competing interestsThe authors declare that they have no competing interests.

Authors’ contributionsKH was responsible for data collection and interpretation and for draftingthe manuscript. KM performed the necropsy and histopathology andprovided histopathology images. KF performed all diagnostic imagingprocedures and selected the appropriate images. MD and CD conducted thegenetic study. BR contributed substantially to the acquisition of data used inthe manuscript. AF contributed to data collection, helped draft themanuscript and finalised the version to be published. All authors haveapproved the final manuscript.

Author details1Department of Veterinary Clinical Sciences Ludwig-Maximilians-Universitaet,Neurology Service, Clinic of Small Animal Medicine, Munich, Germany.2Department of Veterinary Clinical Sciences Ludwig-Maximilians-Universitaet,Section of Clinical & Comparative Neuropathology, Institute of VeterinaryPathology, Munich, Germany. 3Department of Veterinary Clinical SciencesLudwig-Maximilians-Universitaet, Clinic of Small Animal Surgery andReproduction, Munich, Germany; Small Animal Hospital Hüttig, Reutlingen,Germany. 4Institute of Genetics, Vetsuisse Faculty, University of Berne, Berne,Switzerland.

Received: 6 October 2012 Accepted: 14 March 2013Published: 26 March 2013

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doi:10.1186/1746-6148-9-57Cite this article as: Hirschvogel et al.: Magnetic resonance imaging andgenetic investigation of a case of rottweiler leukoencephalomyelopathy.BMC Veterinary Research 2013 9:57.

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