Genetic protein polymorphisms in human saliva: an interpretive review.

The purpose of this review is to summarize recent progress in the field of genetic protein polymorphisms found in human saliva since 1972. Prior to 1972 most of the investigations were related to amylase. The genetics of salivary amylase will not be considered here, since it has recently been thoroughly reviewed elsewhere (Merritt and Karn, 1977). In this review, special attention will be devoted to the complex interrelationships of the proline-rich (Pr), double-band (Db), acidic protein (Pa), and peroxidase (SAPX) systems. The biochemically related Pr, Db, and Pa systems show distinctive genetic patterns, and there are associations between the phenotypes indicating linkage relationships. There is also evidence for probable interaction of products of the Pa and SAPX loci. Electrophoretic properties of these proteins can be defined in several gel systems, permitting an accurate definition of phenotypes. The usefulness and limitations of the different gel systems in the interpretation of these electrophoretic patterns will be illustrated. Allelic frequencies of the systems to be discussed are given in Table I. To aid comprehension, the systems will be discussed in logical rather than historical sequence.