Kidney Disease: A Family Story
By Dr. Barry I. Freedman
When I first started treating patients with kidney disease, I was surprised to find that many expected to eventually need dialysis treatments.
“You know, my grandmother is on dialysis. My uncle too. And my cousin,” they’d say. “I wondered when my turn would come.”
Some patients even knew the schedule at their nearby dialysis center. “Can you get me an 11 o’clock slot on Monday, Wednesday and Friday?” they’d ask. “That way I can carpool with my uncle who is treated on that shift.”
There was nothing in the medical literature then to suggest that kidney disease was inherited or genetic, but my patients knew the disease ran in their families.
Now, 20 years later, my colleagues and I have proven them right.
In the early 1990s, I started taking careful family histories of my patients and discovered clear patterns. A high proportion of African-American patients with kidney disease attributed to high blood pressure, diabetes, lupus or viral infections had a history of kidney disease in their families. Familial clustering of kidney disease was also present in Caucasian patients, but it was less marked.
These patterns were significant because African Americans are four times as likely to have kidney disease as Caucasian Americans. The medical establishment attributed the higher incidence to hypertension, environmental and socio-economic factors. However, the more I listened to my patients, the more persuaded I became that there was a strong genetic link.
As the revolution in genetic research took off, I began working with scientists here at Wake Forest Baptist Medical Center and around the country to pinpoint the gene that seemed responsible for the high frequency of kidney disease. Our multi-center research team found a major gene less than one year ago. In fact, it is one of the strongest genetic effects in a common disease yet discovered.
Although we don’t have a cure yet, we are searching to find one. Now we understand what led to the higher rate of kidney disease among our African- American patients. Kidney disease is a leading cause of disability and death, especially in the Southeast. Across the country, 7.5 out of every 100 African Americans will eventually develop end-stage kidney failure and require dialysis or a kidney transplant. In contrast, the rate among Caucasian Americans is 2 out of every 100.
When I first started at the medical center, many of our patients had to drive one hour each way to Winston-Salem, three times every week, for dialysis treatments. We have since built a network of dialysis centers throughout the region, in places such as Elkin, Yadkinville and Lexington, so that our patients can receive high quality, lifesaving kidney treatments near their homes. Wake Forest Baptist Medical Center kidney doctors travel to see them in their communities. Many patients receive home dialysis treatments using peritoneal dialysis, a procedure that can be done without much equipment and often while the patient sleeps. Our doctors are also working to develop new treatment regimens to improve patient health and longevity. Together, Wake Forest Baptist dialysis centers treat more than 1,500 patients with end-stage kidney disease and our surgeons perform more than 200 kidney transplants each year.
We can’t cure kidney disease once it is severe, but we can slow its progress at earlier stages. This means that early detection is the best prevention against kidney failure. We work with patients who have diabetes to control their blood sugars and many patients take blood pressure medicine, which slows the disease process. Exercise can help patients with kidney disease to control their diabetes and blood pressure. Smoking causes worsening of kidney disease, so if you smoke it’s time to quit.
Our recent discovery of the major genetic link, a gene called APOL1, gives my patients and me new hope.
This gene explains about 70 percent of all non-diabetic kidney failure cases among African Americans, an amazingly high rate of disease. It turns out that nearly 40 percent of all African Americans on dialysis have kidney disease associated with this one gene.
Now that we know the gene, we expect to find new treatments, even a cure, for those patients with a family history of severe kidney disease.
The more I learn, the more I’m reminded of one patient I met in the early 1990s. He was in his mid-20s, and while in good health, he had high blood pressure. When I told him about his blood pressure, here’s what he said: “When do I need to start dialysis?” I was stunned. He had no evidence of kidney disease on blood or urine tests. But he knew what was coming. “Everyone in my family that started with high blood pressure eventually developed kidney failure,” he told me.
Today, we continue to recruit patients and their relatives for studies that will help us better understand how genetic variation causes kidney disease. The Southeast is a great place to study illnesses that run in families, since so many people settle close to home. This makes it easier to locate their relatives and study kidney disease. Most patients are eager to be part of our studies. They want to be part of changing their family’s legacy.
I’m glad that I listened to my patients; their words led us to make an important discovery. This breakthrough will help patients with kidney disease… around the world, as well as in North Carolina.
Dr. Barry Freedman is chief of the section on nephrology at Wake Forest Baptist Medical Center. He may be reached at 336-716-6192.