[The relationship of methylenetetrahydrofolate reductase gene polymorphism and plasma homocysteine levels in type 2 diabetes mellitus patients with diabetic retinopathy].
OBJECTIVE
To evaluate the role of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and plasma homocysteine levels in Chinese patients with type 2 diabetes mellitus and diabetic retinopathy (DR).


METHODS
MTHFR genetic C677T polymorphisms were determined by PCR-restriction fragment length polymorphism. Total plasma homocysteine levels were measured using high-performance liquid chromatography (HPLC) with fluorescence detection.


RESULTS
The frequencies of MTHFR T homogenetic type and CT heterogenetic type and allele T (28.18%, 41.82%, 49.09%) in type 2 diabetic patients with diabetic retinopathy were significantly higher than those in diabetic patients without retinopathy (18.37%,29.59%,33.16%) or the normal controls (17.54%, 28.07%, 31.58%). Howerver, there were no significant differences in the frequency of MTHFR genotype and allele between the type 2 diabetic patients without retinopathy and the normal controls. The presence of T allele appeared to have a strong association with the development of diabetic retinopathy. The odds ratio was 1.94 and the 95% confidence interval was 1.31-2.88. Moreover, the plasma homocysteine levels in patients with TT or CT genotype were markedly higher than those in patients with CC genotype.


CONCLUSIONS
MTHFR gene C677T mutation associated with a predisposition to increase of plasma homocysteine may represent a genetic risk factor for diabetic retinopathy in Chinese type 2 diabetes mellitus.
Sun
Jiazhong
J
Department of Endocrinology, Zhongnan Hospital, Wuhan University,Wuhan, Hubei, 430071 P. R. China. sjz300@163.com
Xu
Yancheng
Y
Zhu
Yilian
Y
Lu
Hongyun
H
Deng
Haohua
H
Fan
Youjun
Y
Sun
Suxin
S
Zhang
Ying
Y
D000328:Adult; D000483:Alleles; D004247:DNA / Q000235:genetics / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications / Q000235:genetics*; D003930:Diabetic Retinopathy / Q000097:blood / Q000209:etiology / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D008875:Middle Aged; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics*; D017354:Point Mutation; D011110:Polymorphism, Genetic
D006710:Homocysteine; D004247:DNA; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D015252:Deoxyribonucleases, Type II Site-Specific; C032229:GANTC-specific type II deoxyribonucleases