Linkage of gene for C2 deficiency and the major histocompatibility complex MHC in man. Family study of a further case.

Close linkage between HL-A and C2 deficiency was first reported by FU and co-workers in 1974. We present here a pedigree of a 31-year-old C2-deficient individual with clinical manifestations of Hodgkins disease. The following markers were tested: C2 levels, factor B polymorphism, blood groups, and enzyme typing. In addition to close linkage between HL-A and C2 deficiency, both parents were heterozygous for Bf (HL-A linked, electrophoretic variation of B). The two HL-A haplotypes closely linked to C2 deficiency are different: 2, W18 and W24, W18. They share, however, the SD2 antigen W18 and the LD type 7a.