MSMDS, mostly caused by heterozygous missense mutation of the ACTA2 altering arginine 179, represents the most severe ACTA2 mutation-associated disease because of the early onset and highly penetrant vascular disease.[1] It leads to aortic and cerebrovascular disease, pulmonary hypertension, hypotonic bladder, intestinal hypoperistalsis and malrotation, and ocular abnormalities.[1]. This evidence concerns the gene ACTA2 and pulmonary arterial hypertension.