Which disorder is a result of uniparental disomy?

Uniparental disomy occurs when both copies of a chromosome—one from the mother and the other from the father—are inherited from only one parent. This genetic phenomenon can lead to specific disorders depending on the genes involved and whether they are imprinted.

Prader-Willi syndrome is a classic example of a disorder caused by uniparental disomy, specifically involving chromosome 15. In this condition, if a child inherits two copies of chromosome 15 from the mother and none from the father, it can lead to the typical features of Prader-Willi syndrome. The paternal allele is normally expressed while the maternal one is silenced, so losing the paternal contribution results in the symptoms associated with this syndrome, such as obesity, developmental delays, and hormonal imbalances.

In contrast, the other disorders listed do not arise from uniparental disomy. Cystic fibrosis is a result of mutations in the CFTR gene on chromosome 7 and follows an autosomal recessive inheritance pattern. Sickle cell disease is caused by a specific mutation in the HBB gene on chromosome 11, also following an autosomal recessive inheritance pattern. Klinefelter syndrome, which involves an extra X chromosome in males (47,XX