OBJECTIVETo Study the effect of C677T and MTHFR gene polymorphism on side effects of HD-MTX in ALL children.

METHODSThe gene polymorphism of C677T A303G and MTHFR C677T were detected by PCR in 98 ALL children from January 2014 to January 2016. The side effects during HD-MTX therapy were observed, and the relationship among GSTP1, MTHFR gene polymorphism and incidence of side effect of HD-MTX were analyzed.

RESULTSAmong 98 ALL children, the gene variation was observed in 61 ALL children (62.24%). Polymorphism study on C677T A303G showed that the gene frequency of A was 84.69%, while that of G was 15.31%; for polymorphism of MTHFR C677T, gene frequency of C was 66.33%, and that of T was 33.67%. Seven patients(7.14%) experienced with bone marrow supression, 23 patients(23.47%) with liver function damage, 15 patients(15.31%) with renal function damage, 48 patients(48.98%) with gastrointestinal reactions and 46 patients(46.94%) with mucosal lesions. After adjustment of sex, age, risk stratification and dosage of MTX, the gene polymorphism had no significant relationship with bone marrow suppression, gastrointestinal reactions and mucosal lesions(P>0.05). However, the number of the mutant genes had statistically significant relationship with liver and renal function damage(P<0.05).

CONCLUSIONThe risk of side effects during HD-MTX therapy increases in ALL children with combined mutation of MTHFR and C677T.