This approach revealed a significant association of rare variation in the aquaporin gene, AQP1, and the transcription factor encoded by SOX17. Of note, both AQP1 and SOX17 were within the top 8 ranked genes in our combined PTV and missense burden test analysis (Supplementary Table 7), providing further confidence in their causative contribution to PAH. Here, AQP1 is linked to pulmonary arterial hypertension.