RTL1

RTL1, also known as retrotransposon-like 1 or PEG11, is an imprinted gene located in the Prader-Will syndrome region on chromosome 15q11-q13 in humans. It is primarily paternally expressed, with the maternal allele silenced by DNA methylation at nearby imprinting control regions. The RTL1 locus contains transcripts derived from retrotransposon-like sequences and is thought to produce protein products, though the coding capacity and exact function remain active areas of research.

Expression of RTL1 is strongest in placental tissue and developing fetal organs, consistent with a role in placental development and fetal growth. In animal models, altered RTL1 expression affects placental morphology and growth, with loss of function leading to placental defects and growth impairment, while increased expression can drive abnormal placental development. The precise mechanisms underlying these effects are not fully understood.

Clinical significance of RTL1 lies in its placement within the paternal gene set of the 15q11-q13 region. Disruption of paternal expression in this domain can contribute to Prader-Will syndrome features. Abnormal regulation of RTL1 has been investigated in studies of placental pathologies and fetal growth disorders, though human data remain limited and definitive conclusions are cautious.

See also: Prader-Will syndrome, genomic imprinting, PEG11.