Early ultrasound prenatal diagnosis of the Meckel — Gruber syndrome in combination with 47,XYY

Abstract

Meckel — Gruber syndrome (MGS) is a rare lethal autosomal recessive disorder characterised by occipital encephalocele, polydactyly and bilateral dysplastic cystic kidneys. A case of prenatal diagnosis of MGS at 12 weeks of gestation is described. The previous pregnancy was terminated at 20 weeks due to polycystic kidneys of the fetus. The transabdominal scan of the present pregnancy revealed occipital encephalocele of the fetus. There was no oligohydramnios, but the fetal urinary bladder was not visualised and both kidneys were enlarged. The transvaginal sonogram demonstrated intracranial space dilatation (6 mm) and encepalocele with posterior fossa cyst, protrunding from the occipital bone deffect. The kidneys had the polycystic structure suggesting cystic dysplasia and there was no evidence of the hands and feet polydactyly. Based on these findings the diagnosis of the MGS was made. Chorionic villus sampling revealed 47,XYY. The family elected to terminate pregnancy and the diagnosis was confirmed by autopsy.