- The human calbindin D28k (CALB1) and calretinin (CALB2) genes are located at 8q21.3----q22.1 and 16q22----q23, respectively, suggesting a common duplication with the carbonic anhydrase isozyme loci. Parmentier, M., Passage, E., Vassart, G., Mattei, M.G. Cytogenet. Cell Genet. (1991)