High resolution chromosome analysis and in situ hybridization on amniotic fluid for diagnosis of a cryptic translocation

We report a cryptic translocation ascertained in a family after the birth of a mentally retarded proband. High resolution chromosome examination revealed that the father had a subtle translocation between chromosome 5 and chromosome 13, 46, XY, t(5;13) (q35.2;q34). Two specific, non-routine techniques were associated for prenatal diagnosis: high resolution cytogenetic studies on the amniotic fluid and fluorescent in situ hybridization with YACs as specific telomeric probes. The fetus had the same cryptic translocation as his father. (C) 1998 John Wiley & Sons, Ltd.