Dr Irfan A. Kazi MD[RD]Radiologist,

Sonosquare Ultrasound Clinic, Hyderabad

IntroductionMeckel Gruber syndrome is a rare autosomal recessive

condition with reported incidence of 2-7 per 1 million births

It is characterised by the triad of :-Renal cysic dysplasia [95-100%]Encephalocele [60-80%]Post axial polydactyly [55-75%]

At least 2 of these features when seen in a fetus with normal karyotype are diagnostic of this syndrome

Clinical presentationA 23 yr old primigravida [with consanguineous

marriage] presented to our clinic for routine antenatal checkup at 15 wks of gestation.

USG done on this patient revealed enlarged kidneys showing numerous cysts & occipital encephalocele

There was no polydactyly. No other abnormalities were noted as per the

gestational age of the fetus Liquor was adequate for gestational age.The fetal karyotyping done did not reveal any

chromosomal anomalyThus a diagnosis of Meckel Gruber Syndrome was

made

Enlarged kidneys are seen which are showing numerous small cysts..

The AC is also consequently increased

Occipital encephalocele with herniation of brain is seen

CNS abnormalities:

Microcephaly, Dandy walker malformationAgenesis of corpus callosumHoloprosencephalyventriculomegaly

This triad may be associated with :-

Facial malformations:

Cleft lip/palateMicrognathiaMicrophthalmiaEar malformationsSloping forehead

Cardiac anomalies:

Septal defectsCoarctation of aorta

Other anomalies:

Small bell shaped chestHepatic fibrosisCryptorchidismAmbiguous genitalia

Trisomy 13

Renal anomalies: in 50%Cystic dysplasia Kidneys may be large, but typically smaller than in meckel gruber syndrome

CNS:Holoprosencephaly in 40%Encephalocele- less common

Extremities:Post axial polydactyly in 75%

Other facial & cardiac anomalies may be seen

Autosomal recessive polycystic kidney disease• Does not have associated encephalocele/polydactyly

Multicystic dysplastic kidney•If it is bilateral -does not have associated encephalocele/polydactyly

Encephalocele•Isolated or with other syndromes-kidneys & extremities are normal

Prognosis & workup Take home message !

It is a lethal condition

Oligohydramnios leads to pulmonary hypoplasia

Most are still born or die within few hours

Karyotyping is done to exclude trisomy 13

Renal cystic dysplasiaEncephalocelePost axial polydactylyAt least 2 features of this triad,

when seen in a fetus with normal karyotype are diagnostic of Meckel Gruber syndrome

USG is an immensely useful tool for identifying this lethal condition

Genetic counselling should be done as there is 25% chance of recurrence