WEDNESDAY, Jan. 3, 2024 -- Variants in certain DNA repair and cancer-predisposing genes are associated with early-onset Merkel cell carcinoma (MCC), according to a study published online Jan. 3 in JAMA Dermatology.

Noreen Mohsin, M.D., from the National Institutes of Health in Bethesda, Maryland, and colleagues prospectively enrolled participants with early-onset and later-onset MCC, defined as disease occurring in individuals younger than 50 years and at age 50 years or older, respectively, to identify genetic risk factors for early onset MCC via genomic sequencing. The analysis included 37 participants with early-onset MCC, 45 with later-onset MCC, and 930 unrelated controls.

The researchers found that 19 percent of the patients with early-onset MCC had well-described variants in genes associated with cancer predisposition; six of the seven patients had variants associated with hereditary cancer syndromes (ATM, BRCA1, BRCA2, and TP53), and one had a variant associated with immunodeficiency and lymphoma (MAGT1). The early-onset cohort was significantly enriched for cancer-predisposing pathogenic or likely pathogenic variants in these five genes compared with unrelated controls (odds ratio, 30.35). In the patients with later-onset MCC, no germline disease variants were identified in these genes. Among patients with MCC, additional variants were identified in DNA repair genes.

"Genetic counseling and cascade testing of potentially affected family members should be considered for patients diagnosed with MCC at age younger than 50 years, with a focus on detecting pathogenic variants in ATM, BRCA1, BRCA2, TP53, MAGT1, or DNA repair genes," the authors write.

One author disclosed being the founder of Moonlight Bio.