SNORD116

SNORD116 is a cluster of small nucleolar RNAs (snoRNAs) located in the Prader-Will syndrome (PWS) region of the human genome on chromosome 15q11-q13. It belongs to the HBII-85 family of C/D box snoRNAs and is encoded within the introns of the imprinted SNRPN transcript, typically expressed from the paternal chromosome. The SNORD116 cluster is frequently disrupted or deleted in Prader-Will syndrome as part of the paternal 15q11-q13 region, contributing to the clinical features of the condition.

The precise molecular function of SNORD116 snoRNAs is not fully established. As with many snoRNAs, they are expected to participate in ribosomal RNA modification, but no specific rRNA methylation targets have been definitively identified for SNORD116. The absence of SNORD116 snoRNAs in humans and in experimental models is associated with features resembling Prader-Willi syndrome, particularly disruptions in growth and energy balance, which points to a role in neurodevelopment and hypothalamic regulation. Nevertheless, the full mechanism by which SNORD116 loss contributes to the PWS phenotype remains unresolved, and other imprinted genes in the region also influence the syndrome's characteristics.

Evolutionarily, the SNORD116 cluster is conserved in placental mammals and is part of the broader imprinted gene landscape at 15q11-q13. Expression is enriched in neural tissues, with prominence in regions relevant to feeding and growth control. Clinically, paternal deletion or disruption of the SNORD116 cluster is considered a major contributor to Prader-Willi syndrome, though the phenotype arises from combined loss of multiple paternal genes in the region. Research continues to clarify the specific functions and therapeutic implications of SNORD116 loss.