We used free text and the medical subject heading (MeSH) terms “amyotrophic lateral sclerosis,” “ALS,” “iron,” “iron metabolism,” “iron accumulation,” “biomarker,” and “iron chelation.” Then, we searched for each marker of iron metabolism (DMT1, TfR1, ferritin, ferroportin, hepcidin, HFE,...) AND ALS (OR “amyotrophic lateral sclerosis”). Here, SLC40A1 is linked to amyotrophic lateral sclerosis.