Zinc functions as a cofactor for numerous enzymes, nuclear factors, and hormones and as an intra- and intercellular signal ion. Members of the zinc transporter (ZNT)/SLC30 subfamily of the cation diffusion facilitator family, such as SLC30A7, permit cellular efflux of zinc (Seve et al., 2004 [PubMed 15154973]).[supplied by OMIM, Mar 2008].