GENETIC POLYMORPHISMS OF THE CST2 LOCUS CODING FOR CYSTATIN SA

A new genetic polymorphism of cystatin SA has been identified in human submandibular-sublingual saliva by means of basic gel electrophoresis and immunoblotting with anti-cystatin S. Two proteins, SA1 and SA2, a re given by two alleles of CST2, viz., CST21 and CST*2. Inheritance i s controlled by two codominant alleles at an autosomal locus. This hyp othesis is supported by studies of 16 families 32 children. Gene frequ encies for CST21 and CST2*2 are 0.935 and 0.065, respectively (n = 34 1). Eighteen amino acids determined among 20 N-terminal residues of cy statin SA2 are identical with the sequence encoded by CST2. Three form s of cystatin S (mono-phosphorylated cystatin S, di-phosphorylated cys tatin S, and non-phosphorelated cystatin S) are present in the 341 sal iva samples tested.