UTRN

UTRN is the gene that encodes utrophin, a cytoskeletal protein related to dystrophin. Utrophin is part of the dystrophin-glycoprotein complex and helps stabilize the sarcolemma, the muscle cell membrane, during contraction. In humans, utrophin is most abundant during development and at the neuromuscular junction, and its levels in adult skeletal muscle are generally lower but can be increased in response to injury or disease. The gene produces multiple utrophin isoforms through alternative splicing, including a full-length form commonly referred to as utrophin A.

Utrophin belongs to the spectrin superfamily and shares functional similarities with dystrophin. It associates with membrane-associated proteins and the actin cytoskeleton, contributing to membrane integrity and signaling at sites such as the neuromuscular junction. Its distribution and regulation are tissue-specific, with expression observed in smooth muscle and certain glial cells in addition to skeletal muscle.

Clinical and research relevance: Utrophin has attracted attention as a potential therapeutic target for Duchenne muscular dystrophy (DMD) because increasing utrophin expression could compensate for dystrophin deficiency in muscle fibers. While animal studies have shown partial functional compensation, no utrophin-based therapy has been approved for humans. Mutations in UTRN have been reported in a small number of individuals with muscular dystrophy-like phenotypes, but such associations are rare and the pathogenic contribution of UTRN variants remains under investigation. Research continues into the regulation of UTRN expression, its isoforms, and its interactions within the dystrophin-glycoprotein complex.