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. This gene;encodes one of the two B type proteins, B1. Alternative splicing results in transcript variants and a duplication of;this gene is associated with autosomal dominant adult-onset leukodystrophy (ADLD).