No association between GSTM1 and GSTT1 deletion polymorphisms and Amyotrophic Lateral Sclerosis: a genetic study in Brazilian patients

The glutathione S-transferases superfamily (GSTs) act on the detoxification process of xenobiotics and oxidative stress products. The relevance of gene-environment interactions in the development of Amyotrophic lateral sclerosis (ALS) encourages further investigation into the role of genetic factors, such as GSTM1 and GSTT1 deletion polymorphisms. This case-control study evaluated the association of GSTM1 and GSTT1 deletion polymorphism and ALS susceptibility. We genotyped 101 case-patients and 119 controls with multiplex real-time PCR (qPCR) and collected clinical and demographic data from medical records and questionnaires. Our findings demonstrated that alcohol intake was predominant in ALS patients and was significantly associated with the development of the disease (p = 0.01). However, we found no association between ALS risk and GSTM1 (p = 0.85) and GSTT1 (p = 0.90) polymorphisms, even when we combined both genotypes. We analyzed a sample of Brazilian patients, a population within which few studies exist about this rare disease. Thus, new insights seeking the relationship between ALS and mutations, polymorphisms, or the expression of other cell detoxification pathway genes should be encouraged and will provide additional information on the role of antioxidant mechanisms and oxidative stress in the pathogenesis of the disease.