Angelman syndrome results from loss of function of a specific gene within the 15q11-q13 region that is maternally expressed due to imprinting. Which gene, when absent on the maternal chromosome, is primarily responsible for the Angelman phenotype?

• A SNRPN
• B NDN
• C UBE3A ✓
• D MKRN3

Explanation

UBE3A encodes a ubiquitin ligase and is the critical gene responsible for Angelman syndrome. It is imprinted and expressed primarily from the maternal allele in certain brain regions. Loss of maternal UBE3A function, whether by deletion, UPD, or mutation, causes Angelman syndrome. SNRPN, NDN, and MKRN3 are paternally expressed imprinted genes in the same region; their loss contributes to Prader-Willi syndrome, not Angelman syndrome.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.