ROBERTSONIAN (15Q-15Q) TRANSLOCATION IN A CHILD WITH ANGELMAN-SYNDROME - EVIDENCE OF UNIPARENTAL DISOMY

A balanced Robertsonian translocation 45,XY,t(15q15q) was detected in a patient with mental retardation, microcephaly, and hypertonia. Delet ion of the 15q11q13 region was unlikely based on fluorescence in situ hybridization studies that revealed hybridization of appropriate DNA p robes to both arms of the Robertsonian chromosome. Inheritance of alle les from 13 highly polymorphic DNA markers on chromosome 15 showed pat ernal uniparental isodisomy. The clinical, cytogenetic, and molecular results are consistent with a diagnosis of Angelman syndrome. (C) 1996 Wiley-Liss, Inc.