While K1 is synthesized in high abundance in epithelial cells in the kidney (in the distal tubule) and in other exocrine glands, K1 deficient mice display only minor renal epithelial abnormalities related to calcium and potassium handling, with mild hypercalciuria and delayed response to dietary potassium load (13, 22, 23). The gene discussed is KRT1; the disease is Hypercalciuria.