Three singe center case control studies (34–36) and one multicenter study (37)Higher homocysteine in mothers (2 studies) (36, 37), fathers and neonates (1 study) (34), vegetarian diet in mothers (1 study) (35), low maternal b12 status (1 study) (36) and low maternal transcobalamin levels (1 study) (37) was associated with higher risk for NTD.Maternal 776C>G polymorphism in TCN2 was strongly predictive of NTD in the offspring (1 study) (37). Here, TCN2 is linked to neural tube defect.