RENATAL DIAGNOSIS OF MOSAIC TETRASOMY 12P TRISOMY 12P BY FLUORESCENT IN-SITU HYBRIDIZATION IN AMNIOTIC-FLUID CELLS - A CASE-REPORT OF PALLISTER-KILLIAN SYNDROME

A prenatally detected case of a rare mosaic tetrasomy 12p/trisomy 12p is reported, presenting as the well-known accessory isochromosome 12p and a supernumerary single 12p marker in 17/24 and 6/24 clones of cult ured amniotic fluid cells, respectively. The chromosomal nature of bot h marker chromosomes was investigated in cultured amniotic fluid cells by fluorescent in situ hybridization with various probes: the 12-cent romeric probes pa12H8 and D12Z3, a whole chromosome 12 paint, and the chromosome 12p-specific paint M28. DNA analysis revealed a maternal or igin of the extra 12p material, After counselling, the parents request ed termination of pregnancy. Inspection and autopsy of the fetus revea led many of the dysmorphisms and internal structural abnormalities of the Pallister-Killian syndrome,