An Age‐Associated Decrease in the Frequency of C4B*Q0 Indicates That Null Alleles of Complement May Affect Health or Survival

We studied the distribution of complement C4, C3, and factor B allotypes in 423 healthy Icelandic subjects from 17 to 89 years of age. A marked decrease was observed in the carrier frequency of variant alleles of complement C4B (C4B(*)Q0) and C3 (C3(*)F). These results confirm our previous observations on Hungarian subjects and suggest a negative effect of C4B(*)Q0 on health or survival.