LRRK2 and amyotrophic lateral sclerosis: This means that this variant in HRNR occurs 1 in 300 Europeans, while other known pathogenic gene variants such as the Gly2019Ser variant of LRRK2 in PD (1 in 2,400 Europeans) or the Arg521Cys variant of FUS in amyotrophic lateral sclerosis (1 in 25,000 Europeans) are much less frequent.