ATP13A3 and pulmonary arterial hypertension: A homozygous V855M variant was identified in a child with early onset PAH leading to early death.31 The other PAH missense variants (L675V, M850I, R858H, and L956P) were heterozygous and found in older patients with PAH.7 Collectively, our data confirm pathogenicity due to a loss of function, although possibly by differing impacts on ATP13A3 protein function, negatively impacting on (i) protein expression, (ii) transport activity, (iii) polyamine homeostasis, and/or (iv) substrate specificity.