Postzygotic Mutations in Beta-Actin Are Associated with Becker's Nevus and Becker's Nevus Syndrome

The study identified recurrent postzygotic mutations in the ACTB gene, specifically p.R147C and p.R147S, in 61% of Becker’s nevi cases, including one case of Becker’s nevus syndrome. These mutations were found exclusively in the pilar muscle lineage and were associated with increased Hedgehog (Hh) pathway signaling, which may disrupt hair follicle and muscle development. The findings suggested that these ACTB mutations underlie the development of Becker’s nevi and potentially contribute to the musculoskeletal abnormalities seen in Becker’s nevus syndrome.