Folate and methionine metabolisms are involved in DNA synthesis and methylation, and polymorphisms in genes of folate metabolizing enzymes have been associated with some forms of cancer. MTHFR is one of the most important genes of this pathway and the C677T polymorphisms of this gene has been found to reduced the MTHFR enzyme activity and it lead to lower folate levels. Low levels of folate during retinogenesis may have increased uracil misincorporation, hypomethylation and, as a consequence, be more likely to develop postzygotic mutations in RB1. The aim of current study is to evaluate association between MTHFR C677T polymorphism with retinoblastoma.

C677T polymorphism was evaluated in 93 retinoblastoma patients and 194 cancer free normal controls using PCR-RFLP and the products were separated on 12% polyacrylamide gels. The results were analyzed using Chi square test and SPSS software.

allelic frequencies of C and T alleles were 0.828 and 0.172 in cases and 0.724 and 0.276 in controls, respectively. Genotypes frequencies of CC, CT and TT in cases were 0.677, 0.301 and 0.022 and in controls were 0.515, 0.418 and 0.067, respectively. Chi square test showed significant differences between cases and controls (P= 0.022).

Frequency of T allele and T containing Genotypes (TT or CT) were significantly lower in patients than in control and the results show a protective effect for T allele. Further studies in larger cohorts are needed to be performed.