Prevalence of the Predisposing Gene MBD4 for Uveal Melanoma.

Abstract

IMPORTANCE: MBD4 monoallelic germline pathogenic and likely pathogenic variants have recently been identified as predisposing to uveal melanoma, a rare primary intraocular tumor, with an estimated 9.15-fold increased risk of developing the disease for pathogenic variant carriers. OBJECTIVE: To assess the risk of developing uveal melanoma for carriers of the MBD4 monoallelic germline pathogenic variant. DESIGN, SETTING, AND PARTICIPANTS: In a case series involving 896 individuals, including 319 who were previously evaluated, germline target-sequencing of MBD4 was offered to every new patient with uveal melanoma at Curie Institute from February 2021 to September 2025. Non-Finnish European participants from the Genome Aggregation Database were used as a reference population. EXPOSURE: Diagnosis of uveal melanoma genetic predisposition. MAIN OUTCOMES AND MEASURES: Prevalence of MBD4 variants. RESULTS: A total of 23 of 896 patients were identified as carrying an MBD4 germline pathogenic or likely pathogenic variant, corresponding to a relative risk of 31.44 (95% CI, 18.18-53.00) of developing uveal melanoma compared with the general population (2-sided Fisher exact test, P&#x2009;<&#x2009;.001). CONCLUSIONS AND RELEVANCE: These findings confirm that MBD4 is an important predisposing gene to uveal melanoma in the French population. This reinforces a strategy of broad patient screening given the therapeutic implications and the consequences of genetic counseling.