Amyotrophic lateral sclerosis (ALS) is an aggressive rapidly progressing degeneration of both upper and lower motor neurons. Clinically, ALS is characterized by rapidly progressing atrophy and paresis of the muscles of the extremities. The genetics of ALS have become more complex in the last 5 years. The SOD gene is still very important; however, in recent years mutations in the genes for TDP-43 and FUS were discovered and also a most interesting intronic repeat expansion of the hexanucleotide repeat in C9ORF72 has been shown to be the most common in ALS. There are other quantitatively less relevant genes, which, however, are meaningful for pathogenetic aspects. It is also necessary to know that the phenotypes associated with ALS genetics have expanded.