Implications of confirmed de novo pathogenic SOD1 mutations

Progress has been made in the study of amyotrophic lateral sclerosis (ALS) genetics in recent years but there remains debate regarding the role of mutations which develop de novo in a patient, rather than being inherited from one or both parents. Theoretically, such mutations should occur but relatively few are reported. The mutation rate is estimated at 1.8×10−8 per nucleotide per generation,1 and therefore all individuals must carry de novo genetic changes. Moreover, ALS-associated mutations are not embryonically lethal and so there is no obvious reason why de novo forms of such mutations should not be present in patients with ALS. Occurrence of de novo mutations could explain minimal or even absent family history for patients carrying mutations which otherwise behave …