The NM_000180.4(GUCY2D):c.839C>G (p.Thr280Arg) variant predicts the substitution of arginine for threonine at position p.280. While the REVEL score is indeterminate (0.58) and does not support a deleterious effect on protein structure, the splicing impact predictor SpliceAI gives a score of 0.46 which is above the ClinGen LCA/eoRD VCEP recommended threshold of ≥0.2 and predicts a damaging impact on splicing (PP3). This variant is absent from gnomAD v4.1.0 (PM2_Supporting) and has been reported in at least 2 unrelated probands with early-onset severe retinal dystrophy who were homozygous for the variant. (1 point, PMIDs: 2642740, 29068479, PM3). The variant has been reported to segregate with childhood-onset severe retinal dystrophy through the proband plus 1 similarly affected relative, with the variant present in the homozygous state (PP1; PMID: 29068479). At least one proband harboring this variant exhibits a phenotype including diagnosis of LCA (0.5 pts), significantly reduced rod ERG (0.5 pts) and extinguished cone ERG (1 pt), decreased peripheral vision (1 pt) and decreased visual acuity (1 pt). The patient's OCT showed retinal structure preserved relative to vision loss (1 pt). (Total points 5.0, PP4). In summary, this variant meets the criteria to be classified as Likely Pathogenic for GUCY2D-related recessive retinopathy based on the ACMG/AMP criteria applied, as specified by the ClinGen LCA/eoRD VCEP: PM3, PP1, PP3, PP4, PM2 supporting. (VCEP specifications version 1.0.0; date of approval 01/22/2025).