PRENATAL-DIAGNOSIS OF A FETUS WITH A HOMOLOGOUS ROBERTSONIAN TRANSLOCATION OF CHROMOSOMES-15

We present a prenatal diagnosis of a de novo homologous Robertsonian t ranslocation involving both chromosomes 15. Amniocentesis was performe d on a 36-year-old woman at 16.5 weeks of gestation, Chromosome analys is documented a 45,XX,der(15;15) (q10;q10) chromosome pattern, No evid ence of a deletion was observed by FISH using a SNRPN DNA probe associ ated with the Prader-Willi/Angelman syndrome critical region. Molecula r studies in the family using six polymorphic markers for chromosome 1 5 and Southern blot analysis of DNA methylation for the CpG island nea r the SNRPN gene showed normal biparental inheritance of chromosome 15 , excluding uniparental disomy. The patient was counseled that her chi ld would not be able to bear offspring without clinical assistance, Ot herwise the health and intellect of her child were not expected to be affected by the translocation, We consider this to be the first prenat al case identified with a balanced der(15;15)(q10;q10) Robertsonian tr anslocation and a phenotypically normal female outcome. Prenatally ide ntified cases of der(15;15)(q10;q10) warrant further investigation by molecular methodology. (C) 1997 Wiley-Liss, Inc.