Fluorescence in situ hybridisation on formalin fixed fetal tissue in the diagnosis of chromosomal syndromes.

Two cases of stillborn children with multiple congenital anomalies are presented. No routine karyotyping was performed. After dysmorphologic evaluation a tentative diagnosis of trisomy 18 and triploidy, respectively, could be made. Fluorescence in situ hybridisation with several chromosome specific probes on formalin fixed paraffin embedded tissue confirmed the suspected diagnosis in both cases. In view of the important consequences for the parents (relatively low recurrence risk, availability of prenatal diagnosis in subsequent pregnancies) fluorescence in situ hybridisation for the common chromosomal aneuploidies should be performed in selected cases of stillborn fetuses with multiple congenital malformations.