Interestingly, when focusing on SLC genes associated with Mendelian disease, we found that population-specific carrier frequency in the general population recapitulated the ethnogeographic variation of various Mendelian disorders with a recessive mode of inheritance, including cystinuria in Jewish individuals, type II citrullinemia in East Asians, and lysinuric protein intolerance in Finns. This evidence concerns the gene CCL21 and citrullinemia type I.