VCX-A is only expressed in testis and may play a role in spermatogenesis or in sex ratio distortion. It is a 186aa peptide that has an estimated molecular weight of ~20kD. It was recently identified that VCX-A is an inhibitor of the decapping enzyme DCP2 and that it stabilized mRNA. It is a noncanonical cap-binding protein that binds to capped RNA but not cap structures lacking RNA. Defects in VCX-A are associated with some forms of X-linked nonspecific mental retardation.