How Rare is This?

I have been hearing about so many different kinds of kidney disease that I’d forgotten which I’d written about. UMOD nephropathy is one that has kept coming up this past week or so. That got me to thinking… yep, I did write about it once before. It seems I had trouble getting any information at that time. Let’s try again. 

To start, here is some of the information about the disease that I included in SlowItDownCKD 2019. 

This is what the U.S. National Library of Medicine at bit.ly/3sykq5O had to say: 

‘Many individuals with uromodulin-associated kidney disease develop high blood levels of a waste product called uric acid. Normally, the kidneys remove uric acid from the blood and transfer it to urine. In this condition, the kidneys are unable to remove uric acid from the blood effectively. A buildup of uric acid can cause gout, which is a form of arthritis resulting from uric acid crystals in the joints. The signs and symptoms of gout may appear as early as a person’s teens in uromodulin-associated kidney disease. 

Uromodulin-associated kidney disease causes slowly progressive kidney disease, with the signs and symptoms usually beginning during the teenage years. The kidneys become less able to filter fluids and waste products from the body as this condition progresses, resulting in kidney failure. Individuals with uromodulin-associated kidney disease typically require either dialysis to remove wastes from the blood or a kidney transplant between the ages of 30 and 70. Occasionally, affected individuals are found to have small kidneys or kidney cysts (medullary cysts).’” 

By the way, the U.S. National Library of Medicine is part of the National Institutes of Health. 

I suspected I could find more information since almost two years have passed and I did. The Genetic and Rare Diseases Information Center (GARD), which is part of the National Center for Advancing Translational Sciences which, in turn, is part of the National Institutes of Health (just as the U.S. National Library of Medicine is) at Bit.ly/35KOalW offered the following:   

Autosomal dominant tubulointerstitial kidney disease due to UMOD mutations (ADTKD–UMOD) is an inherited disorder that causes a gradual loss of kidney function that eventually leads to the need for kidney transplantation or dialysis between the ages of 30 and 70. Patients with ADTKD-UMOD have high blood levels of uric acid before kidney failure develops, and some affected individuals may develop gout. Gout is a form of arthritis (inflammation) that occurs often in the big toe, ankle, knee, or other joints…. ADTKD-UMOD is caused by a mistake (mutation) in the UMOD gene, which leads to the build-up of the altered uromodulin protein in the tubules [Gail here: These are small tubes in your kidneys.] the kidney, leading to slow loss of kidney function. ADTKD-UMOD is inherited in a dominant pattern in families. It is diagnosed based on the symptoms, laboratory testing, family history and genetic testing. Many of the symptoms of ADTKD-UMOD can be treated with medication. For patients whose kidney function worsens to end-stage kidney disease, kidney transplant and dialysis can be used. The long-term outlook for people with ADTKD-UMOD is good, though patients may require dialysis or kidney transplantation between the ages of 30 and 70….” 

I was having a bit of trouble with the different names of the disease, so I turned to the National Center for Biotechnology Information (NCBI) at https://www.ncbi.nlm.nih.gov/books/NBK1356/ for clarification: 

“Autosomal dominant tubulointerstitial kidney disease caused by UMOD pathogenic variants (ADTKD-UMOD) was previously known as familial juvenile hyperuricemic nephropathy type 1 (FJHN1), medullary cystic kidney disease type 2 (MCKD2), and UMOD-associated kidney disease (or uromodulin-associated kidney disease)” 

The NCBI is ultimately also part of (surprise!) the National Institutes of Health. 

Well, that helped but you may also need this definition found in What Is It and How Did I Get It? Early Stage Chronic Kidney Disease’s Glossary: 

Nephropathy: Kidney disease.” 

Hmmm, come to think of it, we could use a few more definitions. Thank you to Medline Plus for the definitions: 

Uremic acid: Uric acid is a chemical created when the body breaks down substances called purines. Purines are normally produced in the body and are also found in some foods and drinks. Foods with high content of purines include liver, anchovies, mackerel, dried beans and peas, and beer. 

UMOD gene: The UMOD gene provides instructions for making a protein called uromodulin. This protein is produced by the kidneys and then excreted from the body in urine. The function of uromodulin remains unclear, although it is known to be the most abundant protein in the urine of healthy individuals. Researchers have suggested that uromodulin may protect against urinary tract infections. It may also help control the amount of water in urine. 

This is quite a bit of information, but we still need the symptoms? According to Wake Forest Baptist Health at bit.ly/3oRN7s8

“There are three common features of this disease: 

Patients develop chronic kidney failure with loss of kidney function beginning in the teenage years and progressing to the need for dialysis or kidney transplantation at an age between 30 and 70 years. Patients have few or no symptoms of kidney disease when they are diagnosed. 

Usually, affected individuals are found to have some loss of kidney function when they undergo blood testing by their doctor as part of a general health screening. A blood test called the serum creatinine level is performed. If the blood creatinine level is above 1, this is usually abnormal and means the kidney is not removing the creatinine from the blood well enough. …. Frequently the doctor does not know why the serum creatinine level is high. Even if a kidney biopsy (the removal of a small piece of kidney tissue) is performed, a correct diagnosis is frequently not made. 

The patient has gout or some member of the family has a history of gout …. Affected individuals have high blood uric acid levels, and this leads to gout. Every affected individual in the family may not have gout, but there are usually at least one or two people in the family who have gout. Gout frequently involves the big toe, the foot, or the knee. The big toe will become extremely tender, and even placing a sheet on the toe will cause pain. In this condition, gout occurs in the late teenage years in both men and women. (In contrast, gout developing in the normal adult population tends to occur in overweight men in their 30’s to 50’s). Family members may develop bumps on their joints called tophi that are deposits of uric acid. 

The disease is likely to be inherited. If a person has the disease, their children have a 1 out of 2 (50%) chance of having the disease. The disease does not skip a generation, though a parent may be less severely affected than their child, and may not have gout or other signs of kidney disease for some time. Therefore, there is usually a strong family history of the condition.” 

Unfortunately, there is no cure for this rare disease – there are medications available to treat the symptoms. Only 400 people worldwide suffer from UMOD Nephropathy. 

Until next week, 

Keep living your life!