In 1999, Wald et al. [5] proposed a new algorithm for risk assessment in sequential screening for DS, which integrated pregnancy-associated plasma protein A (PAPP-A) and fetal nuchal translucency (NT) measured by ultrasonography in the first trimester with alpha-fetoprotein, unconjugated estriol (uE3), free beta-human chorionic gonadotropin (F β-hCG), and inhibin A in the second trimester. The gene discussed is AFP; the disease is Dravet syndrome.