These disorders and their causal genes include autosomal dominant polycystic kidney disease (ADPKD) genes PKD1 and PKD2; Loeys-Dietz syndrome (LDS) genes TGFBR1, TGFBR2, SMAD2, SMAD3, TGFB2, TGFB3, and PMEPA1; vascular Ehlers–Danlos syndrome gene COL3A1; Marfan syndrome gene FBN1; and Microcephalic/Majewski’s Osteodysplastic Primordial Dwarfism Type II gene PCNT. The gene discussed is SMAD3; the disease is autosomal dominant polycystic kidney disease.