In particular, CFTR [CF (MIM: 219700), 16.35% FDR], DMD [Duchenne muscular dystrophy (MIM: 310200), 13.26% FDR], F8 [Hemophilia A (MIM: 306700), 9.51% FDR], FMR1 [FXS (MIM: 300624), 9.21% FDR], PAH [Phenylketonuria (MIM: 612349), 7.70% FDR], and SMN1 [SMA (MIM: 253300), 7.38% FDR] were the top 6 genes providing the highest fetal risk and accounting for ~1 in 823 affected pregnancies and ~60% of overall fetal risk. This evidence concerns the gene CFTR and pulmonary arterial hypertension.