Lamins are a class of intermediate filament proteins that form a matrix on the inner surface of the nuclear envelope. These proteins are found in many different cell types in three different forms (A, B, and C). Lamins A and C are alternatively spliced versions of the LMNA gene. Lamin A has a mass of about 74kDa while Lamin C is 65kDa. Mutations in the LMNA gene are associated with several serious human diseases, including Emery-Dreifuss muscular dystrophy, familial partial lipodystrophy, limb girdle muscular dystrophy, dilated cardiomyopathy, Charcot-Marie-Tooth disease type 2B1, and Hutchinson-Gilford progeria syndrome.