Interleukin gene polymorphisms in age-related macular degeneration.
OBJECTIVE
To investigate polymorphisms in a candidate gene of interleukin (IL) in unrelated Taiwan Chinese patients with late age-related macular degeneration (AMD) and control subjects without AMD.


METHODS
In this retrospective, case-control study, 312 unrelated Taiwan Chinese patients with late AMD and 180 age- and sex-matched control subjects were enrolled. Late AMD was classified as either atrophic (dry) or neovascular (wet) according to the International ARM Epidemiologic Study. Genomic DNA was prepared from peripheral blood obtained from all patients with AMD and control subjects. Polymerase chain reactions were used to analyze 14 single-nucleotide polymorphisms (SNPs) in candidate genes of 5 ILs: IL-1beta(2q14): -511 T/C; IL-6 (7p21): -572 C/G and -596 G/A; IL-8 (4q13-q21): -251 A/T, +781 C/T, +1633 T/C, and +2767 A/T; IL-10 (1q31-q32): -592 A/C, -819 C/T, and -1082 G/A; and IL-18 (11q22.2-q22.3): +105 A/C, -137 C/G, -607 A/C, and -656 T/G.


RESULTS
In the 312 patients with late AMD, dry AMD was diagnosed in 136 and wet AMD in 176. Among the 14 SNPs in the 5 IL genes studied, only the IL-8 +781 C/T SNP was significantly associated with wet AMD (T allele: 46% in wet AMD versus 28% in the control subjects, P = 1.03 x 10(-6), OR = 2.16, 95% CI = 1.58-2.94). The association analysis based on genotypes at both IL-8 +781 C/T and the CFH Y402H demonstrated that the IL-8 +781 C/T to AMD was not significant when analyzed conditional on the presence of the CFH Y402H C risk allele and vice versa. The IL-8 +781 C/T was in low linkage disequilibrium with CFH Y402H (D' = 0.02).


CONCLUSIONS
The data suggest that Taiwan Chinese carriers of the IL-8 +781 T allele, independent of the CFH Y402H polymorphism, are at increased risk of developing wet AMD.
Tsai
Yi-Yu
YY
Department of Ophthalmology, China Medical University Hospital, Taichung, Taiwan.
Lin
Jane-Ming
JM
Wan
Lei
L
Lin
Hui-Ju
HJ
Tsai
Yushin
Y
Lee
Cheng-Chun
CC
Tsai
Chang-Hai
CH
Tsai
Fuu-Jen
FJ
Tseng
Sung-Huei
SH
D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D044466:Asian People / Q000235:genetics; D016022:Case-Control Studies; D020256:Choroidal Neovascularization / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D007378:Interleukins / Q000235:genetics*; D008268:Macular Degeneration / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D012189:Retrospective Studies; D013624:Taiwan / Q000453:epidemiology
D007378:Interleukins