Evidence for the Pathogenicity of a CFH Variant in a Multigenerational Family with Cuticular Drusen

Background and Objectives: Cuticular drusen are a rare form of early-onset drusen maculopathy, which falls within the spectrum of age-related macular degeneration. Previous research suggests that cuticular drusen can result from monogenic inheritance of pathogenic variants in the complement factor H coding CFH gene. These variants impair regulation of the alternative complement pathway, leading to increased central retinal inflammation, progressive tissue damage, and ultimately, vision loss. This study aims to assess the pathogenic potential of the variant NM_000186.4(CFH):c.1318C>T, previously classified as a variant of unknown significance. Materials and Methods: Eight individuals from three generations of a single family underwent ophthalmologic evaluation, including biomicroscopy, ophthalmoscopy, optical coherence tomography, and optical coherence tomography angiography. Subsequently, whole-exome sequencing of the proband's DNA sample was performed. Sanger sequencing was used to validate the whole-exome sequencing results and to assess segregation of the identified variant in the family. The individuals' clinical, instrumental, and genetic data were collected and stored in the database iGENLIT. Results: the heterozygous NM_000186.4(CFH):c.1318C>T variant was detected in six family members. Of these, five have been clinically diagnosed with cuticular drusen. Three affected individuals are currently in their 40s and maintain good visual acuity. In two family members, the drusen progressed to choroidal neovascularization, fibrosis, and atrophy, resulting in profound visual loss at the ages of 54 and 62. One 21-year-old individual also carries the variant, but currently shows no evidence of drusen, likely due to age. Conclusion: In this study, we demonstrated a genotype-phenotype relationship in individuals with the NM_000186.4(CFH):c.1318C>T variant, which suggests its pathogenic role in the development of cuticular drusen and associated complications.