Polycystic kidney disease is one of the leading causes of kidney failure.
"So far, there has been no cure," says Dr. Fouad Chebib, a Mayo Clinic nephrologist.
But for the first time, there is hope: a drug called tolvaptan that the Food and Drug Administration recently approved for treating polycystic kidney disease.
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Polycystic kidney disease is caused by a genetic mutation passed down from parents.
"The patients will start forming kidney cysts," Dr. Chebib says. "Those are fluid-filled sacs in the kidney. So as they are growing, the kidney starts to fill with fluids ... They have multiple, multiple cysts, and that damages the kidney, leading to kidney failure."
But, he says, there is new hope for what has always been a difficult disease.
Dr. Chebib, who was on the Mayo Clinic team researching the drug, says it's not a cure, but it can slow the disease's progression.
"It blocks the thirst hormone," he says. "It's called 'vasopressin.' So, by blocking the thirst hormone and its effect on the kidney, we block the cyst from forming more ... fluids. So what happens is that the cyst doesn't grow as fast."