Other reports of childhood-onset disease include four likely pathogenic variants in a cohort of 2572 PAH cases from a North American PAH biobank [16], plus a Japanese case diagnosed at two years of age with IPAH and patent foramen ovale, who carried heterozygous variants in SOX17 and TBX4, both inherited from an unaffected parent [41]. The gene discussed is TBX4; the disease is pulmonary arterial hypertension.