Genomic imprinting explains why deletion of the same chromosome 15q11-q13 region causes different syndromes depending on parental origin. Maternal deletion at 15q11-q13 causes which syndrome?

• A Prader-Willi syndrome
• B Beckwith-Wiedemann syndrome
• C Russell-Silver syndrome
• D Angelman syndrome ✓

Explanation

Genomic imprinting at 15q11-q13: the paternal allele expresses genes for Prader-Willi (SNRPN, NDN) while the maternal allele expresses UBE3A (ubiquitin ligase). Maternal deletion removes UBE3A → Angelman syndrome (severe intellectual disability, absent speech, seizures, happy demeanor, 'puppet-like' gait). Paternal deletion removes SNRPN/NDN → Prader-Willi syndrome (neonatal hypotonia, hyperphagia, obesity, hypogonadism). Mnemonic: Angelman = Absent speech (maternal gone); Prader-Willi = Paternal gone.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.