The role of single-nucleotide variants of the energy metabolism-linked genes SIRT3, PPARGC1A and APOE in amyotrophic lateral sclerosis risk

Amyotrophic lateral sclerosis (ALS) is a multifactorial disease, possibly with contributions from genetics and lifestyle. We examined variants in genes relevant to energy metabolism and physical activity in a case-control association study, with the aim of assessing genetics and physical activity as contributors to ALS risk. A well-characterized sample of Italian ALS patients (101) and controls (101) from the EURALS Consortium underwent a questionnaire interview on demographic, physical and other lifestyle habits, and venipuncture for DNA extraction. The genes selected were sirtuin 3 (SIRT3), peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PPARGC1A) and apolipoprotein E (APOE). Genetic studies suggested, for the first time, a protective role of the SIRT3 single-nucleotide polymorphism rs4980329 in ALS risk, and a contribution of the APOE-epsilon 2 allele, which was more frequent in ALS patients than in controls. A joint analysis coupling genetic data and sporting activity revealed opposite roles of APOE-epsilon 2 and SIRT3 rs3825075, the former being more frequent in physically active ALS patients and the latter more frequent in physically inactive patients. These findings suggest a contribution to ALS risk of genetic and environmental factors involved in energy metabolism, and stress the importance of a multifactorial analysis for evaluating this risk.