A Novel UPF1 Variant Associated With a Rare UPF1-Related Neurodevelopmental Disorder.

Nonsense-mediated mRNA decay (NMD) plays a crucial role in degrading aberrant transcripts with premature termination codons, with the Up-frameshift (UPF) protein family-UPF1, UPF2, and UPF3A/UPF3B-being vital components of this machinery. While several variants in genes encoding UPF2 and UPF3A/3B have been associated with neurodevelopmental disorders, only three germline UPF1 variants have been reported to date. Here, we report a male patient with a de novo missense variant, p.