A COMPLEX CHROMOSOME REARRANGEMENT WITH AT LEAST 5 BREAKPOINTS STUDIED BY FLUORESCENCE IN-SITU HYBRIDIZATION

A newborn infant with multiple congenital anomalies was diagnosed with an unbalanced translocation of chromosomes 1 and 5. Studies of parent al chromosomes revealed a complex rearrangement in the patient's mothe r involving the exchange of terminal long arms between chromosomes 1 a nd 5 and the insertion of an interstitial segment fi om the same chrom osome 5q into chromosome 2q by high-resolution G-banding. Further stud y of the mother's chromosomes by fluorescent in situ hybridization (FI SH) detected an additional insertion between the rearranged chromosome s 2 and 5, which was not revealed by G-banding. This led to the identi fication of a complex translocation-insertion between 3 chromosomes wi th at least 5 breaks qter;2pter-->2q33::5q21.2-->5q23.2::2q35-->2qter) ] and illustrates the value of FISH as an adjunct to standard cytogene tics, particularly in cases of complex rearrangements. (C) 1997 Wiley- Liss, Inc.