Extensive heterogeneity in patients with ALS with mutations in SOD1 in France

Muratet and colleagues present an update1 on mutations in the cytosolic free radical scavenging enzyme SOD1 in 470 French patients with familial ALS. With the development of gene and antibody therapies targeting SOD1 and with over 220 variants found in SOD1 globally, key questions asked are, if all mutations are pathogenic, do they cause neurodegeneration by the same mechanism? which mutations are to be studied in clinical trials? Obviously, it is advantageous in trials to include patients with the same mutation to get a homogenous study population as possible. The paper is therefore timely and interesting for several reasons. From an epidemiological point of view, 38 of the families are heterozygous for 1 of 27 mutations, but only 5 of the mutations were found in more than one family. The p.Gly94Cys is the most frequent SOD1 mutation in …