Complement factor H polymorphisms in Japanese population with age-related macular degeneration.
OBJECTIVE
To study the frequency of five haplotypes previously reported in the complement factor H (CFH) gene for Japanese patients with age-related macular degeneration (AMD).


METHODS
Genomic DNA was isolated from peripheral blood samples taken from 96 Japanese AMD patients and 89 age-matched controls. All patients were diagnosed as having exudative (wet-type) AMD. The amplified polymerase chain reaction (PCR) products of CFH exons 2, 9, and 13, and intron 6 were analyzed by temperature gradient capillary electrophoresis (TGCE) and by direct sequencing. The haplotypes were identified, and their frequencies were calculated and compared with reported results.


RESULTS
Five haplotypes were identified in the Japanese population including four already reported in the American population. The frequencies of these haplotypes were significantly different between Japanese and American in both control and case groups. The haplotype containing Y402H, which was previously reported to be associated with AMD, was only 4% in the control and case population, with a p value of 0.802. However, two other haplotypes were found as risk factors, which gave an increased likelihood of AMD of 1.9 and 2.5 fold (95% CI 1.12-3.69 and 1.42-6.38). One protective haplotype that decreased the likelihood of AMD by 1.6 fold (95% CI 0.26-0.67) was identified.


CONCLUSIONS
The frequencies for five haplotypes previously identified were analyzed in a Japanese population with AMD. Four previously found haplotypes were identified and one additional haplotype was found. The frequencies of each haplotype were significantly different from that in found Americans affected with AMD. Two of the haplotypes were identified as risk factors and one was considered protective.
National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan. okamotoharu@kankakuki.go.jp
Haru
H
Okamoto
Shinsuke
S
Umeda
Minoru
M
Obazawa
Masayoshi
M
Minami
Toru
T
Noda
Atsushi
A
Mizota
Miki
M
Honda
Minoru
M
Tanaka
Risa
R
Koyama
Ikue
I
Takagi
Yoshihiro
Y
Sakamoto
Yoshihiro
Y
Saito
Yozo
Y
Miyake
Takeshi
T
Iwata
D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000235:genetics*; D016022:Case-Control Studies; D017242:Complement Factor H / Q000235:genetics*; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008268:Macular Degeneration / Q000235:genetics* / Q000517:prevention & control; D008875:Middle Aged; D011110:Polymorphism, Genetic
D017242:Complement Factor H