are the three known urinary glycoproteins that affect the formation of calcium-containing kidney stones or calculus. Tamm–Horsfall protein is part of the matrix in renal calculi but a role in kidney stone formation remains debatable. However, decreased levels of Tamm–Horsfall in urine have been found to be a good indicator of kidney stones. Defects in this gene are associated with the autosomal dominant renal disorders medullary cystic kidney disease-2 (MCKD2) and autosomal dominant tubulointerstitial kidney disease (ADTKD) (previously familial juvenile hyperuricemic nephropathy (FJHN)). These disorders are characterized by juvenile onset of hyperuricemia, gout, and progressive kidney failure. Antibodies to Tamm–Horsfall protein have been seen in various forms of nephritis (e.g., Balkan nephropathy), however, it remains unclear whether there is any pathophysiologic relevance to these findings. Another disease associated with mutations in this gene is Uromodulin-associated Kidney Disease (UKD), a rare autosomal dominant progressive failure of the kidneys. In multiple myeloma, there is often protein cast in the distal convoluted tubule and collecting duct of the kidneys, mainly consisting of immunoglobulin light chain known as Bence Jones protein, but often also containing Tamm–Horsfall protein. This is known as myeloma cast nephropathy. History The glycoprotein was first purified in 1952 by Igor Tamm and Frank Horsfall from the urine of healthy individuals. It was later detected in the urine of all mammals studied. References Further reading External links GeneReviews/NCBI/NIH/UW entry on UMOD-Related Kidney Disease Includes: Familial Juvenile Hyperuricemic Nephropathy, Medullary Cystic Kidney Disease 2 OMIM entries on UMOD-Related Kidney Disease Includes: Familial Juvenile Hyperuricemic Nephropathy, Medullary Cystic Kidney Disease 2 Tamm–Horsfall protein deposition Glycoproteins