The custom designed amplicons cover 18 genes frequently mutated in PDA (ARID1A, BRAF, CDKN2A, CTNNB1, GNAS, IDH1, KDM6A, KRAS, MAP2K4, PIK3CA, RBM10, SF3B1, SMAD4, STK11, TGFBR1, TGFBR2, TP53, and RNF43) (see details in the Supplementary Table), containing 440 DNA oligonucleotide primers designed for 220 amplicons.[12]. The gene discussed is SMAD4; the disease is Patent ductus arteriosus.