In mice, Atp13a2 is widely expressed albeit with higher expression in the brain25 and pathogenic ATP13A2 variants in humans cause an early onset parkinsonism, Kufor–Rakeb syndrome.26  Atp13a3 is also widely expressed in mice, with particularly high expression in liver,25 although in humans potentially pathogenic variants may cause PAH.7 The widespread expression of Atp13a2 and Atp13a3 suggests possible redundancy, but the distinct diseases associated with potentially pathogenic variants in humans suggest some non-redundant roles. Here, ATP13A2 is linked to pulmonary arterial hypertension.