Parotid Proline-Rich Salivary Protein Pc

Karn et al. (1985) identified a new polymorphism, Pc, in human salivary proteins. Two proteins, Pc1 and Pc2, determined by alleles Pc(1) and Pc(2), showed autosomal codominant inheritance. The 2 alleles showed gene frequencies of 0.670 and 0.330 in blacks and 0.461 and 0.539 in whites. Segregation analysis did not suggest the presence of a null allele in either population. Azen et al. (1985) assigned the proline-rich protein (PRP) genes to chromosome 12 by means of a DNA probe derived from one of these and human-mouse somatic cell hybrids. There was complete concordance between this marker and an RFLP in the 12q14-q22 region. By in situ hybridization, Mamula et al. (1985) regionalized the salivary protein gene complex to 12p13.2. Although Pc is clearly a proline-rich salivary protein coded by the gene cluster on 12p, its relation to the 6 gene loci identified there is not known (Azen, 1990).