Single nucleotide polymorphism C677T in the methylenetetrahydrofolate reductase gene might be a genetic risk factor for infertility for Chinese men with azoospermia or severe oligozoospermia

Aim： To analyze the distribution of the single nucleotide polymorphism （SNP） C677T in the methylenetetrahydrofolate reductase （MTHFR） gene in 355 infertile Chinese patients with idiopathic azoospermia or severe oligozoospermia and 252 fertile Chinese men as controls to explore the possible association of the SNP and male infertility. Methods： Using the polymerase chain reaction （PCR）-restriction fragment length polymorphism technique, the allele and genotype distribution of SNP C677T in the MTHFR gene were investigated in both patients and controls. Results： The frequencies of allele T （40.9% vs 30.4%, P = 0.002, odds ration [OR] = 1.58, 95% confidence interval [CI]： 1.24-2.02） and mutant homozygote （TT） （18.3% vs. 11.5%, P = 0.023, OR = 1.72, 95% CI： 1.07-2.76） as well as carrier with allele （TT ＋ CT） （63.4% vs. 49.2%, P = 0.0005, OR = 1.79, 95% CI： 1.29-2.48） in infertile patients were significantly higher than those in controls. After patient stratification, the significant differences in distribution of the SNP between each patient subgroup and control group still remained. Conclusion： Our findings indicate that there is an association of SNP C677T in the MTHFR gene with male infertility, suggesting that this polymorphism might be a genetic risk factor for male infertility in Chinese men.

May headache be the first sign of mutation in the MTHFR gene?

BACKGROUND:Cerebral venous thrombosis(CVT) is a rare disease and it has different etiologies.Inherited or acquired prothrombotic state plays a key role in the development of CVT.METHODS:A 28-year-old man who presented to our emergency department with persistent headache and accompanied by complaints of nausea and vomiting over a week.Neurologic examination revealed bilateral papilledema.Brain computed tomography showed a hyperdense area on the posterior part of the occipital lobe.Brain magnetic resonance imaging and magnetic resonance venography revealed thrombosis of CVT.Homozygous mutations were found for methylenetetrahydrofolate reductase(MTHFR).MTHFR CG677 T gene mutation and blood tests showed elevated homocysteine levels on the etiological screening.There was no other etiology for CVT.RESULTS:Headache and other complaints were improved after treatment of heparin,warfarin,and vitamin B12.No recurrence of symptoms was observed upon outpatient follow-up.CONCLUSION:Since CVT is an important cause of headache,we recommend etiology screening for patients who present with CVT for MTHFR gene mutations and family counseling should be provided.

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. Conclusion 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.