What is UKD?
What is Uromodulin Kidney Disease (UKD)?
UKD is a progressive kidney disease that very slowly degrades kidney function over time. This loss of kidney function does not affect how much urine the patient makes, but instead, the kidneys have trouble filtering out the waste products that the body makes every day. Because we naturally have much more kidney function than we need, patients with this condition do not develop any symptoms of the disease for many years. The first sign of UKD is an increase in the blood creatinine level, which doctors can detect through blood tests. Very small increases in the blood creatinine level may be seen in childhood. The blood creatinine slowly rises over time, though it is different for each person. Patients with this condition frequently need dialysis or a kidney transplant somewhere between age 30 and age 60.
In this disease the kidneys have trouble filtering uric acid, and the blood uric acid level rises. When the blood uric acid level goes up, the uric acid can deposit in joints and cause gout. Gout is a type of inflammation that happens in different joints in the body. It usually happens first in the big toe, foot, ankle, or knee. Gout is very painful, and the affected joint gets hot. Not everyone with UKD has gout, but in most families with this disease, gout is present in several family members. In this condition, gout often starts in the teenage years, which is unusual because typically gout affects middle-aged adults.
There are several kidney diseases that are similar to UKD but have different causes. These include:
- Medullary Cystic Kidney Disease Type 1 (MCKD1); caused by mutations in the MUC1 gene.
- Familial Juvenile Hyperuricemic Nephropathy Type 2 (FJHN2); caused by mutations in the REN gene.
What other names have been used for Uromodulin Kidney Disease (UKD)?
Before the cause of UKD was well understood, medical practitioners named the disease based on the symptoms of the disease. Unfortunately, the symptoms vary across patients, and this has resulted in many names being used to describe this disease. We use Uromodulin Kidney Disease (UKD) to unify all these names, which include:
- Autosomal dominant medullary cystic kidney disease (ADMCKD)
- Familial gout kidney disease
- Familial gouty nephropathy
- Familial hyperuricemic nephropathy
- Familial interstitial nephropathy
- Familial Juvenile Hyperuricemic Nephropathy Type 1 (FJHN1 & FJHN)
- Familial urate nephropathy
- Familial Uromodulin Associated Nephropathy (FUAN)
- Hyperuricemic nephropathy
- Medullary Cystic Kidney Disease Type 2 (MCKD2 & MCKD)
- UMOD Associated Kidney Disease (UAKD & UMAK)
- UMOD related kidney disease
- Uromodulin Associated Kidney Disease (UAKD & UMAK)
- Uromodulin associated nephropathy
- Uromodulin storage disease
What causes Uromodulin Kidney Disease (UKD)?
UKD is caused by mutations in the UMOD gene, which is the gene that contains the instructions for making the uromodulin protein. Uromodulin is only produced in the kidneys and then excreted from the body in urine. It is the most abundant protein in the urine of healthy people. The function of uromodulin is not well understood, but researchers have suggested that uromodulin may protect against urinary tract infections, and help control the amount of water in urine.
The mutations that cause UKD alter the structure of this protein, preventing its release from the kidney cells. This buildup of uromodulin in the kidney cells may trigger the self-destruction of cells, causing progressive kidney disease.
How do people inherit Uromodulin Kidney Disease (UKD)?
This condition is inherited in an autosomal dominant pattern, which means that only one copy of the altered gene in each cell is sufficient to cause this disorder.
In most cases, an affected person has one parent with the condition. Children of affected parents have a 50% chance of developing UKD. For this reason, there are usually several family members who have had kidney failure and gout.
How common is Uromodulin Kidney Disease (UKD)?
According to the National Institute of Health (NIH) in the USA, the prevalence of UKD disease is unknown, but accounts for fewer than 1 percent of cases of kidney disease.