A recent case–control study suggested that high triglycerides may be associated with longer survival, whereas higher levels of cholesterol were associated with a higher mortality [298], while another study explored the role of irisin, a peptide hormone released by muscle and involved in metabolism, showing higher levels of irisin in ALS patients with impaired metabolic status compared to normo-metabolic ALS patients and healthy subjects [299]. The gene discussed is FNDC5; the disease is amyotrophic lateral sclerosis.