The nuclear lamina consists of a two-dimensional matrix of
proteins located next to the inner nuclear membrane. The lamin
family of proteins make up the matrix and are highly conserved in
evolution. During mitosis, the lamina matrix is reversibly
disassembled as the lamin proteins are phosphorylated. Lamin
proteins are thought to be involved in nuclear stability, chromatin
structure and gene expression. Vertebrate lamins consist of two
types, A and B. Through alternate splicing, this gene encodes three
type A lamin isoforms. Mutations in this gene lead to several
diseases: Emery-Dreifuss muscular dystrophy, familial partial
lipodystrophy, limb girdle muscular dystrophy, dilated
cardiomyopathy, Charcot-Marie-Tooth disease, and Hutchinson-Gilford
progeria syndrome.