The NM_000329.3(RPE65):c.544C>T (p.His182Tyr) variant in RPE65 is a missense variant resulting in a substitution of histidine by tyrosine at codon 182. This variant is absent from gnomAD v2.1.1 (PM2_Supporting). This variant has been reported in at least 1 unrelated proband with early-onset severe retinal dystrophy who was homozygous for the variant (0.5 point, PMID: 27874104). This variant has also been reported in 2 unrelated probands with early-onset severe retinal dystrophy who were compound heterozygous with the NM_000329.3(RPE65):c.118G>A (p.Gly40Ser) confirmed in trans (2 points, PMID: 9501220, PMID: 27102010), which was previously classified as pathogenic by the ClinGen LCA / eoRD VCEP (2.5 total points, PM3_Strong). The variant has been reported to segregate with childhood-onset severe retinal dystrophy through the proband plus 2 similarly affected relatives, with the variant present in the homozygous state (PP1_Moderate; PMID: 27874104). This variant is a missense substitution at p.His182, which is located within the active site, a well-characterized functional domain required for enzymatic activity (PM1, PMID: 34492281). The variant exhibited approximately 10% enzymatic activity in a retinoid isomerase assay relative to the wildtype control, which meets the ClinGen LCA / eoRD PS3_Supporting threshold of ≤10% activity, indicating that it triggers a severe defect in protein function (PS3_Supporting, PMID: 16150724). The computational predictor REVEL gives a score of 0.912, which is above the ClinGen LCA / eoRD VCEP threshold of ≥ 0.773 and predicts a damaging effect on RPE65 function (PP3_Moderate). In summary, this variant meets the criteria to be classified as pathogenic for RPE65-related recessive retinopathy based on the ACMG/AMP criteria applied, as specified by the ClinGen LCA/eoRD VCEP: PM2_Supporting, PM3_Strong, PP1_Moderate, PM1, PS3_Supporting, PP3_Moderate. (VCEP specifications version 1.0.0; date of approval 09/21/2023).