Protocadherin Alpha 9 (PCDHa9)

PCDHA9 is 1 of 15 tandemly arranged genes within the PCDHA gene cluster on chromosome 5q31. The 15 PCDHA genes function as 'variable' exons that are individually spliced to a downstream constant region to form distinct PCDHA transcripts. These transcripts encode cadherin-like cell surface proteins that are expressed in neurons and are present at synaptic junctions. The A-type constant region includes 3 exons and encodes the longest cytoplasmic domain. In the B-type constant region, the most 3-prime constant exon is divided into 2, resulting in a C-terminal end of intermediate length. O-type variants lack the constant region exons entirely and instead contain the intronic sequence immediately following the variable exon, including an intronic poly(A) sequence.