CLUL1 (clusterin-like protein 1) is a retina-specific gene located on chromosome 18 that encodes a 338-amino acid protein with structural similarity to the molecular chaperone clusterin 1. The protein is predominantly expressed in cone photoreceptor cells 2, with expression showing developmental regulation peaking during photoreceptor differentiation 1. CLUL1 shares 24% identity and 48% similarity with clusterin, suggesting a role in protein homeostasis, though it exhibits distinct tissue expression patterns and retinal development profiles compared to clusterin 2. Clinically, CLUL1 has been identified as a candidate gene for retinal diseases affecting cone photoreceptors. Genome-wide association studies identified CLUL1 as a novel locus associated with age-related macular degeneration (AMD), the leading cause of blindness in the elderly 3. However, mutation screening of 376 AMD patients found only non-pathogenic sequence variations, with one intronic variant potentially reducing AMD risk 4. CLUL1 was also screened as a positional candidate gene for autosomal dominant high-grade myopia (MYP2) on chromosome 18.31, but no disease-segregating mutations were identified 56. Recent metabolic biomarker studies identified altered CLUL1 plasma expression in women with gestational diabetes mellitus and macrosomia, suggesting broader metabolic relevance 7.