Which genetic syndrome arises from a maternal deletion of chromosome 15q11-q13?

The correct answer is associated with Angelman syndrome, which results from a deletion or mutation in the maternal allele of chromosome 15q11-q13. This genetic syndrome is characterized by severe developmental delays, speech impairment, and distinctive behavioral characteristics, including frequent laughter and a happy demeanor. The critical aspect of Angelman syndrome is that the genetic anomaly must occur in the maternal chromosome, as the paternal chromosome in this region is silenced through a process called genomic imprinting. When the maternal copy is deleted, the necessary genes for normal neurological development and function are lost, leading to the manifestations of the syndrome.

In contrast, Prader-Willi syndrome arises from a deletion on the same region of chromosome 15 but involves the paternal allele. Turner syndrome is not related to chromosome 15 but rather involves a missing or incomplete X chromosome, while Down syndrome is caused by an extra copy of chromosome 21. Thus, the specific deletion on the maternal side of chromosome 15q11-q13 unequivocally links to Angelman syndrome.