PFN1 mutations are also rare in the Catalan population with amyotrophic lateral sclerosis.

Evidence of genetic heterogeneity in ALS has been found, with at least 31 genes being identified to date as causing ALS, and other genes being suggested as risk factors for susceptibility to the disease and for phenotype modifications. In recent years, new molecular genetic methodologies, especially GWAS and exome sequencing, have contributed to the identification of new ALS genes. Some of these genes (SOD1, TARDBP, FUS, and C9orf72) have homogenous frequencies in different populations.