There have been instances whereinitially suggested genes turned out to be—most probably—not pathogenic aftersubsequent studies, including the diverging observations on EIF4G1 mutations in PD patients and healthy subjects [4, 5],as well as the initial identification of ADORA1as disease-causing mutations [82] in afamily who also have PTRHD1 mutations, and thereis ongoing uncertainty on the truly pathogenic variant in the large CanadianMennonite kindred discussed above, where DNAJC13and TMEM230 mutations have been postulated to bedisease-causing [7••, 28••]. This evidence concerns the gene PTRHD1 and Parkinson disease.