GJB2 and hereditary palmoplantar keratoderma: When the genes were ordered based on GP, the most frequently observed were HBB (AD, hemoglobinopathies) for Africans (1/7; 182 million); CFTR (AD/AR, cystic fibrosis and related disorders) for Admixed Americans (1/19; 39 million); ABCA4 (AD/AR, retinal disorders) for Ashkenazi Jews (1/12; 1.34 million), Middle Easterners (1/13; 40 million), non-Finnish Europeans (1/13; 77 million) and South Asians (1/18; 111 million); and GJB2 (AD, palmoplantar keratoderma) for East Asians (1/10; 198 million) and Finnish (1/15; 0.36 million) (Fig. 2B).