Tags: Protein.
CD99 antigen (Cluster of differentiation 99) also known as MIC2 or single-chain type-1 glycoprotein is a heavily O-glycosylated transmembrane protein that is encoded by the CD99 gene in humans. The protein has a mass of 32 kD. Although present on the X chromosome unusually the CD99 gene does not undergo X inactivation and it was the first such pseudo-autosomal gene to be discovered in humans.