PAH and pulmonary arterial hypertension: Upon analyzing the three-dimensional model of PAH generated through the in silico prediction of the genomic variant, we observed that the structural alteration caused by the exon 2 duplication affects the N-terminal autoregulatory tail of PAH, where the BH4 cofactor binding site is, and potentially a region involved in the sapropterin mechanism of action (Arturo et al., 2019).