Parental age and the risk of amyotrophic lateral sclerosis

Sporadic ALS is a multifactorial disease for which there are probably multiple genetic risk factors. An association with increased parental age might suggest there is a role for specific (epi)genetic changes. Previous studies have shown conflicting results on the association between parental age and the risk of ALS. A large, population based study might help in the search for specific (epi)genetic risk factors. We performed a population based, case-control study in the Netherlands. Date of birth of both mother and father was retrieved from the National Register. Multivariate logistic regression analysis was performed in 769 patients with sporadic ALS, 49 patients with a hexanucleotide repeat expansion in C9orf72, and 1929 age-, gender- and geographically-matched controls. Multivariate analyses showed no difference in either paternal or maternal age at delivery (adjusted for age of subject, age of other parent at delivery, and level of education) in patients with sporadic ALS, nor in patients with a hexanucleotide repeat expansion in C9orf72 compared to controls. In conclusion, parental age was not associated with an increased risk of ALS in our study. (Epi)genetic alterations that are associated with increased parental age are not, therefore, likely to contribute to the aetiology of sporadic ALS.