OBJECTIVETo evaluate the role of polymorphism in the neurogenic differentiation factor 1(Neuro D) gene in Chinese patients with type 2 diabetes mellitus.

METHODSThe genotypes of codon 45 variant (GCC-->ACC) in the Neuro D gene were determined by mismatch PCR-restriction fragment length polymorphism assay in 448 Chinese, including 124 subjects with normal glucose tolerance and 324 patients with type 2 diabetes mellitus. The diabetic patients were divided into two groups cutting off with the age of 40 at onset.

RESULTSNo homozygote of the Ala45Thr variant was found in these subjects. The frequencies of AT heterozygous type were significantly higher in early-onset type 2 diabetic group than those in the control group and in the late-onset type 2 diabetic group (chi(2)=7.85, P=0.005; chi(2)=8.81, P=0.003). The frequencies of Thr45 allele in the early-onset type 2 diabetic group were significantly different from those of the control group (13.4% vs 5.2%, chi(2)=7.15, P=0.008) and the late-onset type 2 diabetic group (13.4% vs 5.8%, chi(2)=8.13, P=0.004). The presence of Thr45 allele was shown to have an association with early-onset type 2 diabetes (OR=2.52, 95% CI: 1.42-4.49). Furthermore, the subjects carrying the variant appeared to have lower serum concentration of C-peptide in diabetic group. However, the frequencies of polymorphism genotypes of Neuro D gene showed no difference between the late-onset type 2 diabetic group and the control group.

CONCLUSIONThe genetic polymorphism in the Neuro D is associated with the development of early-onset type 2 diabetes. The presence of Thr45 allele may represent a risk factor for early-onset type 2 diabetes among Chinese.

Alleles ; Basic Helix-Loop-Helix Transcription Factors ; DNA ; genetics ; metabolism ; DNA Restriction Enzymes ; metabolism ; DNA-Binding Proteins ; genetics ; Diabetes Mellitus, Type 2 ; genetics ; Female ; Gene Frequency ; Genotype ; Humans ; Male ; Middle Aged ; Mutation, Missense ; Polymorphism, Genetic ; Trans-Activators ; genetics

OBJECTIVETo evaluate the role of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and plasma homocysteine levels in patients with type 2 diabetes mellitus and diabetic retinopathy (DR).

METHODSTotal 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.

RESULTSThe 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.

CONCLUSIONMTHFR 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.

Aged ; Diabetes Mellitus, Type 2 ; complications ; Diabetic Retinopathy ; etiology ; Female ; Genotype ; Homocysteine ; blood ; Humans ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; Middle Aged ; Mutation ; Oxidoreductases Acting on CH-NH Group Donors ; genetics ; Polymorphism, Genetic

OBJECTIVETo 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).

METHODSMTHFR 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.

RESULTSThe 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.

CONCLUSIONMTHFR 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.

Adult ; Alleles ; DNA ; genetics ; metabolism ; Deoxyribonucleases, Type II Site-Specific ; metabolism ; Diabetes Mellitus, Type 2 ; blood ; complications ; genetics ; Diabetic Retinopathy ; blood ; etiology ; genetics ; Female ; Gene Frequency ; Genotype ; Homocysteine ; blood ; Humans ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; Middle Aged ; Oxidoreductases Acting on CH-NH Group Donors ; genetics ; Point Mutation ; Polymorphism, Genetic