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


METHODS
Total of 208 patients with type 2 diabetes mellitus and 57 controls were recruited into the study. MTHFR genetic C677T polymorphisms were determined by PCR-RFLP. Plasma total homocysteine levels were measured using high-performance liquid chromatography (HPLC) with fluorescence detection.


RESULTS
The frequencies of MTHFR TT homogeneous type, CT heterogeneous type and allele T (28.18%, 41.82%, 49.09%) were significantly higher in the type 2 diabetes mellitus with diabetic retinopathy group than those without retinopathy (18.37%, 29.59%, 33.16%) and those of controls (17.54%, 28.07%, 31.58%). The presence of the T allele appeared to have a strong association with the development of diabetic retinopathy. The odds ratio was 1.94 with a 95% confidence interval of 1.31 - 2.88. Moreover, plasma homocysteine levels were remarkably higher in patients with TT or CT genotype than in patients with the CC genotype.


CONCLUSIONS
MTHFR gene C677T mutation associated with a predisposition to increased plasma homocysteine levels may be considered as a genetic risk factor for diabetic microangiopathy (such as DR) in Chinese patients with type 2 diabetes mellitus.
Sun
Jiazhong
J
Department of Endocrinology, Zhongnan Hospital, Wuhan University, Wuhan 430071, China. sj2300@163.com
Xu
Yancheng
Y
Zhu
Yilian
Y
Lu
Hongyun
H
Deng
Haohua
H
Fan
Youyun
Y
Sun
Suxin
S
Zhang
Ying
Y
D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003930:Diabetic Retinopathy / Q000209:etiology*; D005260:Female; D005838:Genotype; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D008875:Middle Aged; D009154:Mutation; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics*; D011110:Polymorphism, Genetic
D006710:Homocysteine; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2)