Platelets, February 2013; 24(1): 81–84

Copyright � 2013 Informa UK Ltd.

ISSN: 0953-7104 print/1369-1635 online

DOI: 10.3109/09537104.2012.658108

LETTER TO THE EDITOR

A family with bolzano-type Bernard–Soulier syndrome carries a benignA1939T MYH9 mutation

SUSMITA N. SARANGI1, MARC GOLIGHTLY2, JIM WEBER3, & EDWARD L. CHAN4

1Division of Pediatric Hematology/Oncology, Steven and Alexandra Cohen Children’s Medical Center of New York, New

Hyde Park, NY 11040, USA, 2Department of Pathology, Stony Brook University Medical Center, Stony Brook, NY

11794-8111, USA, 3Prevention Genetics, Marshfield, WI 54449, USA, and 4Division of Pediatric Hematology/

Oncology, Stony Brook University Medical Center, Stony Brook, NY 11794-8111, USA

Acute onset, isolated thrombocytopenia in

well-appearing children is commonly due to

immune thrombocytopenic purpura (ITP). Most

children recover their platelet counts within 6–12

months. However, a small percentage of these

patients will have persistent thrombocytopenia.

While many of them develop chronic ITP, there are

other rare causes of macrothrombocytopenia that the

clinician should consider. Other differential diag-

noses include MYH9-related thrombocytopenia syn-

dromes, Mediterranean macrothrombocytopenia

(also known as autosomal dominant Bernard–

Soulier syndrome; BSS), velocardiofacial (VCF)

syndrome, familial platelet disorder with associated

myeloid malignancy, Jacobsen and gray platelet

syndromes [1]. Since these other diagnoses are

rare, it is not economically feasible to pursue

workup for each condition in all patients with

persistent macrothrombocytopenia. However, a thor-

ough history including a detailed family history and

ethnicity, a carefully conducted physical examina-

tion, peripheral blood smear review, and the platelet

count level can clue the clinician to narrow the

workup and make the correct diagnosis. We report a

case of a 2-year old girl who presented with acute

ITP and was subsequently found to have autosomal

dominant form of BSS. This case illustrates how

persistent macrothrombocytopenia is not always due

to chronic ITP; clues in the history, exam and

peripheral smear should not be overlooked in order

to reach the correct diagnosis. During the workup,

we also discovered a clinically benign MYH9

mutation.

A previously healthy 2-year-old female presented

with a week long history of easy bruising of the lower

extremities. She had an upper respiratory infection,

a month prior to presentation. There were no other

bleeding symptoms. She did not have systemic

symptoms of pallor, weight loss, or fever. Her past

medical history was only significant for two intrau-

terine transfusions for ABO incompatibility at

7 months gestational age. Her newborn course was

uneventful thereafter, and she reached all develop-

mental milestones. Her family history was significant

for thrombocytopenia on the paternal side with

several members including the father having asymp-

tomatic thrombocytopenia. Figure 1(a) shows the

family tree of the patient and her affected relatives.

One paternal uncle had succumbed to leukemia. Her

physical examination was normal except for bruises

on bilateral lower extremities, chest, and abdomen.

There were no petechiae, wet purpura, hematoma, or

ecchymoses. She was eumorphic in appearance with

normal cardiac and chest exam; there was no

lymphadenopathy or hepatosplenomegaly.

Laboratory evaluation revealed a total white blood

cell count of 9� 103/mm3, hemoglobin 11.5 g/dL,

platelet count 14 000/mm3 with a mean platelet

volume (MPV) of 11.5 fL (8–12 fL). Peripheral

blood smear showed no blasts and no inclusion

bodies in the neutrophils; there were many large

platelets with adequate granulation (Figure 1(b)).

Correspondence: E. L. Chan, Division of Pediatric Hematology/Oncology, Stony Brook University Medical Center, HSC T-11, 020,

101 Nicolls Road, Stony Brook, NY 11794-8111, USA. Tel: 91 631 4447720. Fax: 91 631 4442785. E-mail: Edward.Chan@sbumed.org

(received 1 September 2011; revised 5 January 2012; accepted 9 January 2012)

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Serum chemistries, liver function tests, and platelet

function screen were normal.

Due to the acute onset of thrombocytopenia in

this well-appearing child, an initial diagnosis of ITP

was made. The patient was given 50 mg/kg Rho(d)

immune globulin, following which, her platelet count

rose to 23 000/mm3 within 48 h. On subsequent

follow-up, her platelet count increased to 279 000/

mm3. However, it started to decline, a month after

treatment and remained in the range 90–120 000/

mm3 over the year. Macrothrombocytes also per-

sisted (MPV in the 10–13 fL range). Clinically, she

had no further bruises or bleeding episodes. The

persistent mild macrothrombocytopenia and the

unusual family history clued us to workup an

inherited (primary) thrombocytopenia. The paternal

family history suggested an autosomal dominant

mode of inheritance, of which MYH9-related syn-

dromes are part of the differential. MYH9 gene

mutation analysis of the patient interestingly showed

the heterozygous G5815A missense mutation in exon

40 (Figure 2(a)), where other causative MYH9

mutations have been found [2]. This mutation

results in a change of amino acid at position 1939

from alanine to threonine. To determine if this is a

causative mutation, we performed blood counts and

MYH9 gene analyses on both parents. While the

father had a platelet count of 130 000/mm3, the

mother’s platelet count was normal (240 000/mm3).

Surprisingly, the patient inherited the A1939T

MYH9 mutation from the mother and not the

father. With these results, we concluded that the

A1939T mutation is a benign, non-synonymous,

single-nucleotide polymorphism.

The absence of dysmorphology, cardiac findings,

and developmental disabilities ruled out VCF/

DiGeorge and Jacobsen syndromes. The normal

platelet staining was not consistent with gray platelet

syndrome. While there was a paternal uncle with a

history of leukemia, familial platelet disorder with

associated myeloid malignancy usually associates

with abnormal platelet aggregation [3]. A normal

platelet response to adenosine diphosphate and

epinephrine in this patient was therefore not con-

sistent with this diagnosis. Given the Italian back-

ground, we suspected Mediterranean

macrothrombocytopenia. To investigate further, the

expressions of platelet membrane glycoproteins:

GPIIb/IIIa(CD41), GPIb�(CD42b), and

GPIV(CD36) were analyzed by flow cytometry.

While GPIb� expression was reduced in the patient,

GPIIb/IIIa and GPIV expressions were both

increased (Figure 1(c)). This pattern of platelet

glycoprotein expression has been previously

Figure 1. Clinical and laboratory features. (a) Pedigree of the family. Affected family members are shaded in black, while the unaffected

family members are shaded in white. The patient is represented in gray and indicated by the arrow. (b) Blood smear of the patient. The

arrow showed a macrothrombocyte. (c) Flow cytometry analysis of platelet glycoproteins. Tracings of flow cytometry with antibodies against

GPIIb/IIIa, GPIb�, and GPIV were shown.

82 S. N. Sarangi et al.

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described for patients with autosomal dominant BSS

[4, 5]. To confirm the diagnosis, we performed

GPIb� mutation screen. We found the heterozygous,

C515T or A156V mutation (Figure 2(b)) and

confirmed the diagnosis of autosomal dominant or

Bolzano-type BSS in this patient/family [4, 6].

BSS is a rare inherited platelet disorder, char-

acterized by variable thrombocytopenia and large

defective platelets. The majority of BSS cases are

transmitted in an autosomal recessive manner [7].

BSS cases that have an autosomal dominant trait

were only recently described [4, 8]. In fact,

Mediterranean macrothrombocytopenia is now

recognized to be an autosomal dominant form of

BSS or the Bolzano-type BSS [4]. We described here

an American Italian family who presented with mild

thrombocytopenia and found to have Bolzano-type

BSS. This case is worth discussing not only because

the diagnosis is rare, but also the approach that was

taken to reach the diagnosis can be a learning point

for hematologists who evaluated patients with persis-

tent thrombocytopenia. While ITP is by far the most

common diagnosis in children presented with

macrothrombocytopenia, there are occasional out-

liners that we should be aware of. A thorough history

and physical exam are critical in alerting the

clinicians to these potential rare diagnoses. In our

case, the unusual family history, their ancestry, and

the benign physical exam raised the possibility of an

inherited thrombocytopenia disorder. During our

workup, we incidentally discovered a MYH9 muta-

tion. We eventually found this to be a benign

mutation and ruled out MYH9 disorders in this

patient. Multiple sequence alignment analysis by the

PolyPhen-2 program also predicts the A1939T

MYH9 mutation to be benign. The program aligned

over 300 protein sequences of human MYHIIA

(MYH9 gene product) homologs; a representation of

these data is shown in Figure 2(c). Taken together,

this confirmed the benign nature of the A1939T

MYH9 mutation.

Declaration of interest: Dr Jim Weber is the

president of Prevention Genetics that offer the

MYH9 and GPIb� genetic testings. Dr Edward

L. Chan is the recipient of a mentored research

Figure 2. MYH9 and GPIb� mutations. (a) DNA sequences of the G5815A missense mutation in exon 40 of the MYH9 gene. The arrow

points to the change in the nucleotide. (b) DNA sequences of the C515T missense mutation in the GPIb� gene. The arrow points to the

change in the nucleotide. (c) A representative sequence alignment data of the human MYHIIA amino acid sequence with the amino acid

sequences of homologs in different species. The affected amino acid position 1939 is shown in red. Abbreviations: Hu, Homo sapiens; Gg,

gallus gallus; Xl, xenopus laevis; Dr, danio rerio (zebrafish); Mm, macaca mulatta; Phsc, pediculus humanus subsp. corporis (body louse);

Dy, drosophila yakuba (fruit fly); Hs, harpegnathos saltator; Hm, hydra magnipapillata; Ds, drosophila simulans. Noted that several

homologs of human MYHIIA have threonine or amino acids with polar uncharged side chains (i.e., serine, glutamine, or asparagine) in

position 1939.

Bolzano-type Bernard-Soulier syndrome 83

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scholar grant in applied and clinical research from

the American Cancer Society (117718-MRSG-09-

172-01-CCE).

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