Circulating Biomarkers in Muscular Dystrophies: Disease and Therapy Monitoring

Muscular dystrophies are a group of inherited disorders that primarily affect the muscle tissues. Across the muscular dystrophies, symptoms commonly compromise the quality of life in all areas of functioning. It is well noted that muscular dystrophies need reliable and measurable biomarkers that will monitor the progress of the disease and evaluate the potential therapeutic approaches. In this review, we analyze the current findings regarding the development of blood-based circulating biomarkers for different types of muscular dystrophies. We emphasize those muscular dystrophies that gained particular interest for the development of biomarkers, including Duchenne muscular dystrophy, Becker muscular dystrophy, myotonic dystrophy types 1 and 2, Ullrich congenital muscular dystrophy, congenital muscular dystrophy type 1A, Facioscapulohumeral muscular dystrophy, and limb-girdle muscular dystrophy types 2A, 2B, 2C, and 2D, recently renamed as limb-girdle muscular dystrophy R1 calpain3-related, R2 dysferlin-related, R5 γ-sarcoglycan-related, and R3 α-sarcoglycan-related. This review highlights the up-to-date progress in the development of biomarkers at the level of proteins, lipids, and metabolites, as well as microRNAs (miRNAs) that currently are the main potential biomarker candidates in muscular dystrophies.