Almost all complement component 9 (C9) deficiency in Japan shows Arg95Stop
mutation of C9 gene. Therefore, we studied the prevalence of Arg95Stop muta
tion of C9 gene among 78 patients with SLE to elucidate the assocation of S
LE and C9 deficiency. The Arg95Stop carrier frequency showed no significant
difference between SLE patients and controls. Thus, C9 deficiency is not i
mplicated in SLE susceptibility.