J o u r n a l o f C a s e s i nObs te trics & G ynecology

J Cases Obstet Gynecol, 2017;4(3):72-75

Case Report

A rare case of Meckel-Gruber syndrome: Antenatal diagnosis

Nidhi Gupta1,*, Seema Singhal2

1Department of Obstetrics & Gynaecology, Hamdard Institute of Medical Sciences and Research & HAHC Hospital, New Delhi2Department of Obstetrics & Gynaecology, All India Medical Institute of Medical sciences & Research, New Delhi

AbstractMeckel-Gruber syndrome (MGS) is a lethal autosomal recessive condition which is rarely reported. Polycystic kidneys, polydacty-ly, occipital encephalocele are the diagnostic triad for MGS. 24 year old G2P1L1 having a consanguineous marriage at 20 weeks of ges-tation on detailed level II anomaly scan showed bilateral enlarged polycystic kidneys with increased echogenicity, absent urinary blad-der, posterior occipital encephalocele, bowing of femur, absent liquor. Features were suggestive of Meckel-Gruber syndrome and baby delivered vaginally. Gross examination and autopsy confirmed the diagnosis. Early diagnosis is important with ultrasound as early as 11- 14 weeks, chorionic villous sampling at 14 weeks and targeted scan in early second trimester in every pregnancy to detect these anomalies.

Key Words:Meckel Gruber Syndrome, occipital encephalocele, genetic counselling

Introduction

Article History:Received: 03/02/2017Accepted: 29/04/2017

*Correspondence: Nidhi GuptaAddress: VMMC & SJH Obstetrics and gynaecology –New DelhiTel: 08800358203e-mail: drnidhigupta19@gmail.com

Journal of Cases in Obstetrics & Gynecology72

Meckel-Gruber syndrome (MGS) was originally described by Meckel in 1822 & later by Gruber in 1934. [1] MGS is also called Dysencephalia Splanchnicocystica. [1] This syn-drome is seen in all races and ethnic communities, highest incidence in the Finnish population (1in 9000). [2] Among Indians it is more common in Gujrati’s population. 200 re-ported cases till date with an equal incidence in both sexes. Defective gene for MKS is found to be on Chromosome bands 17q21-q24, 11q13 and 8q24. [3] This results in 100% mortality either intra-uterine or in immediate neonatal period.This syndrome is having a classical triad of multicystic dysplasia of kidney, occipital encephalocele, and polydac-tyly, which are observed in 100%, 90%, and 83.3% cases,

respectively. Besides the clinically recognized classic mal-formations, it can be variably associated with oral clefting, central nervous system (CNS) malformations such as anen-cephaly, holoprosencephaly, polymicrogyria, cerebellar hy-poplasia, pulmonary hypoplasia, and hepatic fibrosis. [4, 5]MKS is a rare disease and invariably lethal in early infan-cy, large clinical series of patients that address epidemio-logical and clinical findings are scarce. There is also very limited data published on any type of birth outcomes—live births (LB), fetal deaths (FD), and terminations of pregnan-cy after prenatal diagnosis (TOPFA) in MKS patients. [6]The aim of this case report is to increase the awareness among obstetricians and radiologists regarding this rare and lethal syndrome. All the foetuses with any congenital malformation should advice autopsy so that if MKS is pres-ent then recurrence risk can be explained to the parents.

Case Presentation

A 24 year old G2P1L1 having a consanguineous mar-riage presented to Safdarjung outpatient department at 20

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weeks of gestation. She was having an ultrasound report suggesting fetal anomaly and was admitted in view of same USG. On examination, her vitals were stable, uterine height was 16- 18 weeks and liquor seemed to be clinically re-duced. Her previous pregnancy resulted in a full term nor-mal vaginal delivery 2 years back. Baby boy was healthy and alive. After admission detailed level II anomaly scan was done showing following feature as shown in Figure 1.

Diagnosis of MECKEL-GRUBER SYNDROME was made on the basis of characterstic traid. Patient was induced af-ter taking informed written consent and delivered vaginal-ly without any intra-partum or postpartum complications. Gross examination of the baby was done and following findings like absent urinary bladder, posterior occipital encephalocele, bowing of femur, absent liquor, large ab-dominal masses and normal female genitalia were noted. The baby’s karyotype analysis has been found as 46,XX. Parents were given the option of autopsy and karyotyping. They were willing for the same. Autopsy was done and the findings were enumerated below and shown in Figure 4.Patient was discharged in stable condition after 4 days. On discharge, patient was explained about the 25% re-currence chance. So importance of prenatal counsel-ling and early detection in next pregnancy by ultra-sonography as early as 11- 14 weeks was told to her.

Discussion

Meckel Gruber syndrome is a rare autosomal recessive disorder, involving multiple systems. [1] This syndrome is having very high recurrence risk so high vigilant ap-proach should be kept in mind to diagnose this syndrome. A large number of case reports have already been report-ed but only few were having all the features suggestive of the syndrome. So we are reporting this case as our case was having all the features specially the classical traid of this syndrome and it was diagnosed at an early gesta-tion which was not so common in the earlier case reports. In our case, all features typical of MGS were diagnosed in antenatal period by targeted level scan at 20 weeks of gesta-tion. The final diagnosis was made after autopsy of the fetus. Meckel Gruber syndrome can be associated with wide va-riety of abnormalities, although the classical triad includes dysplastic kidneys (95-100%), occipital encephalocele (80-90%) and polydactyly (75-85%) [7]. Presence of 2 of the 3 classical findings or 2 other anomalies in addition to one classical finding is sufficient for the diagnosis of MGS [8]. One of the most constant features of MGS is occipital encephalocele, a neural tube defect. MGS accounts for 5% of all neural tube defects [9]. Hence presence of oc-cipital encephalocele indicates the need to search for other abnormalities to assess the recurrence risk in fu-

Figure 1.

Bilateral enlarged polycystic kidneys with increased echogenicity

Figure 2.

Occipital encephalocele is shown

ture pregnancy. In general recurrence of a neural tube defect is 1-3% in a given family, whereas recurrence of MGS is 25% due to autosomal inheritance pattern [9]. In our case, occipital encephalocele was present.Kidneys are grossly enlarged (10 to 20 times) due to cystic changes which can be palpated as abdominal masses [7].

Cystic dysplasia of the kidneys is the constant characteristic feature of MGS leading to oligohydramnios which results in pulmonary hypoplasia. All these features were present in our case. Other urinary system abnormalities may include horse shoe kidney, missing ureters and hypoplastic urinary bladder [9]. In our case, these abnormalities were absent. Postaxial polydactyly is a frequent finding in MGS [10]. Club foot is common because of oligohydram-nios [9]. In our case, postaxial polydactyly with presence of sixth digit was seen in all four limbs.Periportal fibrosis with bile duct proliferation is anoth-er common finding in MGS [7]. Other organ involve-ment include cardiac malformations, hypoplastic or am-biguous genitalia, cleft lip, cleft palate, fissured tongue, atypical face with short nose, low set ears, micrognath-ia, short neck, shortening and bowing of long tubular bones [7, 10]. In the present case, however the hepat-ic, cardiac and genital malformations were not present.MGS has to be differentiated from other syndromes. The most likely syndrome to be confused with MGS is tri-somy 13 [8]. Although the dismal outcome is the same for both, the recurrence rate is different. Trisomy 13 is

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Gupta et al.

mostly sporadic with low recurrence rate whereas MGS has 25% recurrence rate. Other syndromes similar to MGS are trisomy 18, Joubert syndrome, Bardet –Bie-dle syndrome and Smith- Lemli-Obitz syndrome [8, 11].Meckel Gruber syndrome is a lethal disorder with a high re-currence risk (25%). In countries with high rates of consan-guineous marriage, one should be careful and genetic coun-selling should be advised. In the cases with consecutive losses of pregnancy or previously affected pregnancy, early diagnosis is important. Ultrasound as early as 11- 14 weeks, chorionic villous sampling at 14 weeks and targeted scan in early second trimester in every pregnancy to detect these anomalies help in making diagnosis. [7, 8] Recurrence risk is to be explained to the family in first affected pregnancy.

AcknowledgementNone

Declaration of InterestNone

Figure 3.

Post-axial polydactyl of all the four limbs is shown.

Figure 4.

Autopsy findings which demonstrate bilateral en-larged polycystic kidneys, pulmonary hypoplasia and absent urinary bladder.

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