The protocadherin beta cluster is one of three related gene clusters tandemly linked on chromosome five. The protocadherin genes have an immunoglobulin-like genomic organization, suggesting that a novel mechanism may be involved in their regulation and expression. The beta cluster contains 16 genes and 3 pseudogenes. Each gene product contains 6 extracellular cadherin domains and a cytoplasmic tail that diverges from other cadherin superfamily members. Unlike the alpha and gamma clusters, the beta cluster has a variable region but lacks a constant region. Without this downstream region of shared exons, each transcript encodes a unique cytoplasmic tail. The specific functions of these one-exon gene products are unknown; however, they are thought to play a critical role in the establishment and function of specific cell-cell neural connections. [provided by RefSeq, Jul 2008]