PRENATAL AND POSTNATAL INVESTIGATION OF A CASE WITH MILLER-DIEKER SYNDROME DUE TO A FAMILIAL CRYPTIC TRANSLOCATION T(17-20) (P13.3-Q13.3) DETECTED BY FLUORESCENCE IN-SITU HYBRIDIZATION

We present here a case report of a fetus with a kidney anomaly and dil ated occipital horns, detected initially by echoscopy at 29 weeks' ame norrhoea. After 31 weeks of gestation, the proband was born with clini cal symptoms of Miller-Dieker syndrome. This was subsequently confirme d by fluorescence in situ hybridization (FISH), but not by conventiona l cytogenetic analysis. FISH using a cocktail of cosmids (c197-2, c197 -4, c197-9) from the Miller-Dieker critical region showed a deletion o f 17p13.3 in one homologue of chromosome 17. Additional FISH studies r evealed a subtle 17p;20q translocation in the father, his sister, and the paternal grandmother. Hence, our patient is a carrier of an unbala nced 17;20 translocation resulting in a partial deletion of 17p and a partial trisomy 20q. Whenever kidney anomalies and dilated occipital h orns are observed together with polyhydramnios during prenatal ultraso und examination, the possibility of Miller-Dieker syndrome should be s uspected. In such cases, prenatal and/or postnatal chromosome studies should also include FISH analysis with the appropriate probes. (C) 199 7 by John Wiley & Sons, Ltd.