This may appear surprising but is entirely consistent with current hypotheses of ALS causation, in which the odds ratio conferred by genetic variants and age of onset of first symptoms are not correlated, even within the same family (e.g., TARDBP, FUS; Abel et al., 2012, Al-Chalabi and Hardiman, 2013, van Rheenen et al., 2016). Here, FUS is linked to amyotrophic lateral sclerosis.