ALDH2 and hydrops fetalis: Also among the most decreased pathways in the HF.SAAR vs. HF.Ctrl comparison was the WP term, “tryptophan metabolism” (WP79) consisting of proteins involved in the de novo biosynthesis of NAD+ alongside several dehydrogenases (e.g., ALDH1A1, ALDH2, ALDH3A2, HADH, and HSD17B10) which function in NAD+/NADH use (Figure S6A-C).