A 5-year-old boy presents with obesity, intellectual disability, hypotonia, and hyperphagia. Genetic analysis reveals a deletion on chromosome 15 that was inherited from his father. This clinical presentation is most consistent with which genetic disorder?

The correct answer to the question "A 5-year-old boy presents with obesity, intellectual disability, hypotonia, and hyperphagia. Genetic analysis reveals a deletion on chromosome 15 that was inherited from his father. This clinical presentation is most consistent with which genetic disorder?" is Option B: Prader-Willi syndrome.

The other options — A) Angelman syndrome, C) Fragile X syndrome, D) Huntington disease — are incorrect for this USMLE Exam Prep question. As explained above: Prader-Willi syndrome is caused by the loss of function of specific genes on chromosome 15 (15q11-q13), typically due to a paternal deletion or maternal uniparental disomy. It is characterized by hyp…