Deletion and Uniparental Disomy Involving the Same Maternal Chromosome 15

Abstract
Genomic imprinting on chromosome 15q11q13 results in two disparate syndromes: Prader-Willi syndrome, in which the paternal 15q11q13 is lacking, and Angelman syndrome, in which the maternal 15q11q13 is lacking1. Loss of a parental region may be due to either physical deletion or uniparental disomy. Uniparental disomy arises when both copies (alleles) of a gene or chromosome are inherited from the same parent, which can result in either identical alleles (isodisomy) or different alleles (heterodisomy)2,3.