As luck would have it, I am a member of one of those black families in which fatal kidney disease has struck. So I have more than a passing interest in this work.
The statistics are startling: Though African-Americans are 12 percent of the population, we represent about a third of the kidney failures. Kidney disease is about five times more likely to affect African-Americans than other groups. We represent about 35 percent of the people waiting for transplants.
Pollak’s group of researchers isolated a gene at the root of the disease. Known as APOL1, it is a variant that wards off sleeping sickness, a disease mainly borne by tsetse flies that kills tens of thousands of Africans a year.
Sleeping sickness is unknown in North America, but the gene is carried by as many as 12 percent of African-Americans. And carriers are five times more likely than whites to develop nondiabetic kidney disease.
Pollak estimates the genetic mutation evolved thousands of years ago.
“Until recently, it was more important to be protected against sleeping sickness than kidney disease,’’ said Pollak, using the term recently in the relative sense. “These genetic variants are so common that I don’t even like using the word ‘mutation,’ ’’ he said. “It’s really very common, and explains almost all of the variation’’ between ethnic groups.
Those who inherit the gene from one parent have a slightly elevated risk of kidney disease, he explained. But those who get it from both parents have more than 10 times the likelihood of developing kidney disease as the general population.
As with any mystery, many questions abound: Why do some people at high risk develop kidney disease, while other people don’t? If the gene is the cause, what’s the treatment? Could there ever be a cure? These are all questions Pollak is wrestling with in his lab near Fenway Park.
People with advanced kidney disease have limited options. The major courses of treatment are dialysis, which is debilitating, or transplant. That may not change for years, but Pollak’s discovery could be an important first step. Certainly, any progress would be important to many people who wonder if their family histories indicate risk.
My mother died at age 60 in 1993, after more than 20 years on dialysis. She and her doctor strongly suspected that her mother had died of the same thing - their symptoms were similar - though her medical care in the late 1940s was so spotty that it was impossible to say for sure. Thousands of families could tell similar stories. Though kidney disease doesn’t have the public profile of, say, sickle cell anemia, its effects are no less devastating.
Though he has been researching ethnicity and kidney disease for 15 years, Pollak may be closer to the beginning than the end. “We want to understand - at the level of the molecule and the cell - how these are damaging kidneys,’’ he said. “If we can understand that, we can begin treating people with kidney disease - and even better, prevent people at high risk from getting it.’’
