ATP13A3 and pulmonary arterial hypertension: In a European-wide PAH cohort study, we identified 11 rare heterozygous ATP13A3 variants with protein-truncating variants overrepresented (6 of 11), suggesting a loss of function in PAH.7 Since then, more ATP13A3 variants have been reported in other PAH patient cohorts.8–10 Although ATP13A3 is expressed in various cell types, including pulmonary vascular cells, pulmonary macrophages, and dendritic cells,7,11,12 its function remains unclear.