Prenatal diagnosis of a homologous Robertsonian translocation involving chromosome 15

We report the prenatal diagnosis of a fetus with a de now Robertsonian tran slocation: 45,XY,der(15;15) (q10;q10). Although Robertsonian translocations are common chromosomal rearrangements, those involving homologous chromoso mes are infrequent. Since chromosome 15 is imprinted, uniparental disomy (U PD) is a concern when chromosomal rearrangements involving chromosome 15 ar e identified. In the present case, UPD studies showed normal biparental inh eritance. In contrast to the fact that most homologous acrocentric rearrang ements are isochromosomes, these results indicate postzygotic formation of a Robertsonian translocation between biparentally inherited chromosomes 15. Copyright (C) 2001 John Wiley & Sons, Ltd.