To date, over 30 types of LGMD are identified, each caused by mutations in a different gene. New subtypes continue to be discovered, so the current list is almost certainly incomplete. Each subtype has specific features, such as age of onset of symptoms, rate of progression, particular muscles involved, and whether there is heart and respiratory involvement. Because a large number of genes cause LGMD and variable clinical presentation, determining the specific type of LGMD of a particular patient is challenging.