APPLICATION OF FLUORESCENCE IN-SITU HYBRIDIZATION FOR EARLY PRENATAL-DIAGNOSIS OF PARTIAL TRISOMY 6P MONOSOMY 6Q DUE TO A FAMILIAL PERICENTRIC-INVERSION/

We report the prenatal diagnosis of a karyotype 46,XY,rec(6)dup p, inv (6) (p23q27) mat detected by fluorescence in situ hybridization using chromosome 6pter and 6qter specific DNA markers. This partial duplicat ion-deletion (6p12-->pter; 6q27-->qter) emanated from a balanced peric entric inversion 46,XX inv(6) (p23q27)pat present in the mother. The p henotypes of two relatives with the same unbalanced anomaly are descri bed. This report illustrates the sensitivity and specificity of fluore scence in situ hybridization (FISH) and its benefit in rapid and unequ ivocal prenatal diagnosis of subtle chromosomal rearrangements.