Cytotoxic and regulatory T-cell molecule (CRTAM) Homo sapiens The CRTAM gene is upregulated in CD4 (see MIM 186940)-positive and CD8 (see CD8A; MIM 186910)-positive T cells and encodes a type I transmembrane protein with V and C1-like Ig domains (Yeh et al. 2008 [PubMed 18329370]). [supplied by OMIM, Feb 2009],