Typing of the nt343C>T (R95X) allele of the C9 gene by PCR-SSP and the allele frequency of R95X in five ethnic populations

C9-R95X Polymorphism in Patients with Neovascular Age-Related Macular Degeneration

“…The frequency of those with C9-R95X was 6.05% for control subjects, which was slightly less than the reported frequency of approximately 7% in the Japanese population. [23][24][25]32 No difference was detected in the carrier frequency between older and younger subjects in this study. This result confirms that the haploinsufficiency of C9 has no overt effect on the mortality of the C9-R95X carriers.…”

“…23 The carrier frequency of a null mutation (R95X) in the C9 gene (C9-R95X) is estimated to be approximately 7%, which is higher than in other populations, among them Koreans (1.6%-2.0%), Chinese (0.4%-1.0%), Thais (3.7%), Germans (0%), and Italians (0%). [23][24][25] The lack of C9 is associated with an increased risk for meningococcal meningitis 26 or an inhibition of complement-mediated hemolysis in paroxysmal nocturnal hemoglobinuria, 27 indicating its important role in the inflammation mediated by the complement system. Furthermore, the parents of the C9-defective patients, presumed heterozygotes of C9 mutation, were found to have approximately half the TCC-mediated hemolytic activity found in subjects with normal C9, 26 suggesting that the haploinsufficiency in C9 significantly compromises the overall function of TCC in humans.…”