Alzheimer's disease in Brazilian elderly has a relation with homocysteine but not with MTHFR polymorphisms

Objective: To investigate the association between total plasma homocysteine concentration, C677T and A1298C polymorphisms in MTHFR gene and Alzheimer's disease (AD) development. Method: Forty-three patients with probable (63%) and possible (37%) AD and 50 non-demented controls were evaluated. Groups did not differ as to gender, age, scholar years, diabetes, alcohol and coffee intake and physical activity. Total plasma homocysteine (Hcy) levels were determined by HPLC and genotyping for MTHFR by PCR/RFLP. Mann-Whitney "U" test was used to compare quantitative variable, Fisher-Freeman-Halton test to compare genotypes and allele proportions and Chi-square test to other qualitative variables. Results: AD patients presented higher total plasma Hcy levels than controls and the difference was statistically significant. No differences in the C677T and A1298C MTHFR polymorphisms distributions were found between patients and controls. Plasma homocysteine concentration did not change with MTHFR genotypes. Conclusion: Our data confirms the association between increased plasma Hcy concentration and AD and suggests that neither C677T nor A1298C MTHFR polymorphisms contributed to genetic susceptibility for AD in elderly individuals in the Northeast of Brazil.