A new coding region polymorphism of human IgLC2

A new allelic form of the human IgLC2 gene is described. The marker involve s a T to C substitution in the C lambda2 constant region gene, a silent sub stitution at amino acid coding position 178 (YAASS (Y) under bar LSL) and t wo substitutions in the 3'-flanking region. Analysis of IgLC2 alleles in a total of 60 individuals has indicated a frequency of 0.32 for the new allel e, which has been designated IgLC2*B2. The *B1 and *B2 alleles encode T and C, respectively, at nucleotide position 212 in the IgLC2 coding region. Bo th the *B1 and *B2 alleles are found in individuals homozygous for the sing le-copy RFLP allele of IgLC2/IgLC3 (8 kb EcoRI). Knowledge of alleles of th is marker will be important fur studies on the expression of the IgLC2, and IgLC3 isotypes in normal and autoimmune lymphocyte populations, as the cod ing regions of the two isotypes differ only at this position. The marker wi ll also be useful in further studies of linkage with other IgLV and IgLC ma rkers and to establish possible correlations with susceptibility to autoimm une disorders.