SNURFSNRPN

SNURFSNRPN is a locus on human chromosome 15q11-q13 that encompasses the SNURF and SNRPN genes in a bidirectional transcription unit. The region forms part of the Prader-Willi syndrome critical region and hosts multiple noncoding RNAs, including the SNORD116 and SNORD115 snoRNA clusters embedded in introns of the SNURF-SNRPN transcript.

The SNURF and SNRPN genes are expressed primarily from the paternal allele due to genomic imprinting; maternal copies are silenced by methylation. The locus produces two protein-coding transcripts (SNURF and SNRPN) and a long noncoding RNA; the region also hosts a dense array of small nucleolar RNAs that contribute to ribosomal RNA modification and processing.

Functionally, the SNURF-SNRPN unit participates in pre-mRNA splicing through snRNP components; the SNRPN gene encodes the SmN protein, essential for snRNP assembly. The imprinting status of the locus is governed by the Prader-Willi syndrome imprinting center; disruptions such as paternal deletions, maternal uniparental disomy, or imprinting defects lead to Prader-Willi syndrome features, while Angelman syndrome is associated with loss of maternal expression in the same region.

Clinical significance: SNURFSNRPN is central to the molecular basis of Prader-Willi syndrome; testing often includes analysis of the 15q11-q13 region for deletions, uniparental disomy, and imprinting defects. Research continues to explore the roles of the intronic SNORD clusters in neurodevelopment.