Molecular bases for human complement C7 polymorphisms, C7*3 and C7*4

Deficiencies of the Complement System

“…10,11,140 There may an increased frequency in Moroccan Sephardic Jewish families, although true population studies have not been performed. Neisserial infections (predominantly meningococcal) have occurred in 60% of reported cases of C7-deficient individuals.…”

“…The mutations causing C7 deficiency are diverse, 139,140 although founder mutations are seen in the Irish and the Moroccan Sephardic Jews. A second type of C7 deficiency has been described in which the quantity of C7 is diminished and the protein exhibits an altered isoelectric point.…”

Deficiencies of the complement MAC II gene cluster (C6, C7, C9): is subtotal C6 deficiency of particular evolutionary benefit?

“…Several polymorphisms have been detected for the MAC II gene cluster genes, listed in detail elsewhere [20] (note typing error: the C7 m /N polymorphism is due to 1759 A/C [23] not 1769 A/C as listed in [20], Dr B. Sanchez, personal communication), or published recently for C6 [24,25], C7 [26–28] and C9 [29]. The whole set of alleles can form informative haplotypes whereby complement deficiency genes can be traced within families [20,26], also applied for the case in this journal issue [17].…”