C19orf44 is a nuclear protein essential for retinal function with demonstrated roles in maintaining photoreceptor health and potentially kidney function regulation. Primary function: C19orf44 localizes to the nucleus in cultured cells and shows cell cycle-dependent expression, being downregulated during mitosis, suggesting involvement in cell cycle regulation or transcriptional processes 1. In the retina, the protein localizes to the outer nuclear layer and outer plexiform layer, where photoreceptors and synaptic transmission occur 1. Mechanism: While the precise biochemical function remains undefined, C19orf44 is annotated for protein binding capability and appears critical for maintaining retinal photoreceptor integrity and function. Disease relevance: Biallelic loss-of-function variants in C19orf44 cause autosomal recessive inherited retinal disease characterized by late-onset patchy perifoveal chorioretinal atrophy and progressive rod-cone degeneration 12. The homozygous c.549_550del p.(Ser185ProfsTer2) variant is the most common pathogenic mutation identified 1. Additionally, C19orf44 was identified as a candidate locus in genome-wide association studies for estimated glomerular filtration rate slope, suggesting potential involvement in kidney function regulation 3. Clinical significance: C19orf44 mutations represent a novel genetic cause of late-onset retinal degeneration with Stargardt-like phenotype, expanding the genetic landscape of inherited retinal diseases and enabling improved genetic diagnosis in affected families 2.