Four main categories of genes can potentially play a role in the development of dental caries: genes responsible for enamel evolution including AMELX, AMELY, ENAM, and AQP5; genes responsible for saliva production and synthesis including CA6 (carbonic anhydrase 6) and AQP5; genes responsible for immunological responses including LTF (encoding lactoferrin); and genes responsible for carbohydrate metabolism including ESRRB (oestrogen-related receptor β). The gene discussed is AQP5; the disease is dental caries.