Uromodulin-associated kidney disease

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 2, 2016
StartDiseasesUromodulin-associated kidney disease

Uromodulin-associated kidney disease (or UKD) is a genetic disorder that stops the kidneys from properly filtering waste products such as uric acid or creatinine from the blood. UKD is a progressive kidney disease that usually requires dialysis or a kidney transplant. Patients have been diagnosed as early as their teenage years as a result of presenting with gout or increased creatinine levels in their blood.

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Definition & Facts

Uromodulin-associated kidney disease is inherited and is more common among those with a family history of the disease. This disease involves scarring and lesions in the kidneys. Kidney failure and a host of other problems associated with the buildup of waste products in the bloodstream such as the formation of cysts on or in the kidneys or ureter may ensue.

One of the waste products that build up in the kidneys of people with uromodulin-associated kidney disease is uric acid, which causes gout when there is too much of it present in the body. Gout is a serious inflammation of the joints that often presents first as a painful swelling of the big toe, ankle, or knee. Gout as a result of kidney disease often begins in the teenage years, which is unusual because gout generally affects people in middle age and older. Another name for uromodulin-associated kidney disease is familial gout kidney disease.

Other documented diseases that follow a similar progression to uromodulin-associated kidney disease are medullary cystic kidney disease type 1 and familial juvenile hyperuricemic nephropathy. Both of these are also brought about by mutations to genes that affect kidney formation.

Symptoms & Complaints

A common sign of uromodulin-associated kidney disease is abnormally high creatinine levels in the blood that have increased over time. Creatinine is a byproduct of normal muscle metabolism. High levels of it show that the kidneys are not filtering blood properly.

A second common sign of UKD is gout appearing in people much younger than those who usually develop it, while the third most common sign is abnormally high levels of uric acid present in the affected patient's urine. 

Causes

UKD is an inheritable disease named for uromodulin, a protein that is manufactured in the kidneys and excreted in the urine. It is the most common protein found in the urine of healthy people. The genetic mutation that brings about UKD changes the physical structure of uromodulin and effectively prevents it from being released by the kidneys. It is the buildup of this and other proteins in the bloodstream that causes kidney problems.

UAKD is an autosomal dominant disorder; an affected person only needs to possess a single copy of the genetic mutation in order to have the disease. Children of even one parent with uromodulin-associated kidney disease are 50 percent likely to develop it.

Diagnosis & Tests

Diagnosing uromodulin-associated kidney disease can be difficult as some patients afflicted show no symptoms other than high creatinine levels in their blood until they are much older. A doctor suspecting UKD due to the presence of high uric acid, creatinine, or the presentation of gout may order creatinine serum tests, uric acid level tests, or a genetic test that looks specifically for genetic mutations.

An ultrasound may be used to check for small or cystic kidneys. A kidney biopsy may be performed by a surgeon who will then send over the tiny piece of the kidney that has been extracted from the patient's kidney to be studied under a microscope in order to check for the buildup of waste products in the tissues, allowing for the most accurate diagnosis. 

Treatment & Therapy

Uromodulin-associated kidney disease may be treated with drug therapy, surgery and rehabilitation, or palliative care. Surgery would include kidney transplant, though dialysis is often prescribed before transplantation as the lists for kidney donations may be long and it takes time to find matching donors. Dialysis comes with added stress and reduced ability of the patient to do many normal daily activities. Allopurinol may be prescribed to reduce gout symptoms; it can reduce uric acid. Prednisone may also be prescribed to treat gout.

Prevention & Prophylaxis

Inherited genetic disorders are unpreventable. Prospective parents may wish to pursue genetic counseling to assess the risk that they will pass along genetic mutations to their offspring.

Patients should avoid both prescription and over-the-counter drugs known to cause kidney damage, such as certain analgesics. While nonsteroidal anti-inflammatory drugs like ibuprofen may help treat gout, they should not be taken daily over the long term because they may cause damage.