We believe that the effect that PPARδ exerts in protecting the integrity of the vascular structure of the aorta could be slightly counteracting the damaging effect produced by a defective fibrillin 1 present in patients with MFS, and that in keeping with this hypothesis, missense variants in the PPARD gene could be decreasing its protective function of the vascular structure and promoting the severe aortic phenotype in these patients. The gene discussed is PPARD; the disease is Marfan syndrome.