Heterozygous mutations in several of these genes have been associated with congenital disorders, for example, GLI3 in polydactyly syndromes [45], and PORCN in focal dermal hypoplasia (Goltz syndrome) [46, 47], suggesting that the changes that we observe in relation to arsenic exposure may have important implications for infant and long-term health. This evidence concerns the gene GLI3 and focal dermal hypoplasia.