Approximately 20 inherited disorders of kidney transport occurring in man have so far been defined. Most of these diseases have characteristic clinical profiles. They can be divided into four groups: 1) the amino acid transport mutations which include the cystinurias, hyperdibasicaminoaciduria, Joseph syndrome, Hartnup disease, and the methionine malabsorption syndrome: 2) the sugar transport mutations characterized by glucose (renal glucosuria), and glucose-galactose malabsorption; 3) the electrolyte and water transport disorders, among which are familial hypophosphatemic rickets, vitamin D-dependent rickets, pseudohypoparathyroidism, proximal and distal renal tubular acidosis, and nephrogenic diabetes insipidus; and 4) the "mixed" kidney transport mutations such as the "Busby", Fanconi, Lowe, Luder-Sheldon syndromes, and glucoglycinuria.