UMOD (Uromodulin, also known as Tamm-Horsfall protein) is the most abundant protein in mammalian urine under physiological conditions. It is thought to function as a constitutive inhibitor of calcium crystallization in renal fluids. Excretion of this protein in urine may provide defense against urinary tract infections caused by uropathogenic bacteria. Furthermore, defects in this gene are associated with the renal disorders medullary cystic kidney disease-2 (MCKD2), glomerulocystic kidney disease with hyperuricemia and isosthenuria (GCKDHI), and familial juvenile hyperuricemic nephropathy (FJHN). In immunohistochemistry of normal tissue, UMOD has cytoplasmic positivity in distal renal tubules in the kidney. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804;