Final answer:
Prader-Willi syndrome is caused by genetic alterations on chromosome 15, specifically impacting the SNRPN gene, which is related to imprinting defects. SNRPN is the correct answer, as it encodes a splicing factor important for brain development.
Step-by-step explanation:
Prader-Willi syndrome (PWS) is a complex genetic disorder that affects multiple systems of the body and leads to symptoms such as unrelenting hunger and obesity. This condition involves the loss of function of several genes on chromosome 15 due to genomic imprinting, where only one parent's gene copy is active while the other is silenced.
The question specifically asks for the name of the gene associated with the imprinting defect that causes PWS. The gene encoding for a splicing factor and is most often associated with PWS due to an imprinting defect is SNRPN (small nuclear ribonucleoprotein polypeptide N).
Therefore, the correct answer is SNRPN, which plays a critical role in the normal development and function, particularly in the brain, and its deficiency is associated with the characteristics of Prader-Willi syndrome.