Doctors used to call autosomal dominant polycystic kidney disease (ADPKD) adult polycystic kidney disease. That’s because kids who carry one of two genes that cause it usually don’t feel sick. But ADPKD is a dominant genetic disease. Unlike many other conditions, it takes just one faulty copy of a gene to have ADPKD.
What that means is, for every child of a parent with the condition, the odds of APDKD are the same as the flip of a coin. A genetic test could give you the answer from birth or even before. But there’s a lot that an early gene test can’t tell you. That’s because ADPKD symptoms can vary a lot, even within the same family. Either way, the worst symptoms don’t show up until much later in life.
“To the children, it often feels a lot less severe,” says Charlotte Gimpel, MD, a pediatric nephrologist at Medical Center -- University of Freiburg in Germany. “Adults get huge kidneys and can have a lot of pain until finally their kidneys fail and they need dialysis. It’s a severe disease for adults. For children, it used to be said that it’s asymptomatic.”
What Are Early ADPKD Signs?
Gimpel says the idea that kids with ADPKD don’t have any symptoms isn’t “really true,” though. Some kids already will have pain in their sides or back. They may have urinary tract infections (UTIs), kidney stones, or blood in the urine from cysts that already have started forming in the kidneys. Gimpel says kids may have trouble staying dry through the night if their kidneys aren’t working as well as they should.
“More children than we used to think get hypertension or proteinuria” (extra protein in their urine that’s an early sign of kidney damage), she says, “It doesn’t feel like you’re ill, but you can treat it.”
As doctors have begun to catch these early signs of ADPKD, they’ve started to change how they treat kids who may have the condition. “It used to be ‘keep your fingers off’ and don’t bother them with thinking about what you might have until they’re adults and can decide for themselves,” Gimpel says.
There’s no treatment to stop the cysts or future kidney problems. A drug to treat ADPKD is now approved for adults, but there’s still no way to treat ADPKD in kids. But doctors can help in other ways.
“If you leave them alone altogether, you miss the 20% who have a treatable condition,” Gimpel says. “You can't really cure cystic disease, but treating hypertension is important for slowing progression [of kidney problems].”
ADPKD affects other parts of the body, too. Adults with it can have problems in the liver, pancreas, intestines, and heart. But, Gimpel says, there’s no sign these issues happen early in life, and kids don’t need extra screening.
Should You Test Your Kids?
You don’t need to be sure of ADPKD in a child to tackle early signs as they arise, Gimpel says.
Making sure not to miss those who could use early treatment is as simple as keeping tabs on blood pressure. That’s key, Gimpel says, given that feelings about testing kids vary widely in families affected over generations by ADPKD.
“Parents feel different,” Gimpel says. “Some prefer not to know and want to put it in the back of their minds. Others really want to know. If parents and child really want to know before a child is 18, it can be OK to do genetic testing.”
But, there’s no cure for ADPKD and no way to treat it in kids. Experts think early intervention may help, but data on that is lacking.
“The consensus is: We don't recommend screening [kids for ADPKD] because there’s no treatment available to stall progression,” says Christian Hanna, MD, a pediatric nephrologist at the Mayo Clinic. “There’s no FDA-approved treatment. There’s no clear evidence that detection [of ADPKD] in children with no symptoms will improve outcomes.”
Healthy Living and Mental Health
This isn’t to say that nothing can be done, Hanna says. Kids with ADPKD or at high risk may benefit from early education on healthy living. It’s a good idea for them to avoid salty foods and drink plenty of water. Exercise helps, but if a child already has kidney pain or cysts, it’s best to avoid contact sports like football or lacrosse.
Don’t overlook the challenges for kids’ mental health. Kids may have seen their grandparents die from kidney problems, Gimpel says. They may see a parent with ADPKD living in pain. Whether or not a child has early signs, families need to think about how to talk about ADPKD with their kids. Parents should tell kids about their risks for ADPKD by the time they turn 18, if not before.
"When a child reaches adulthood without understanding their own health risks, she says, it’s often hard for them to change their mindset about the future.
“Talk to children in an age-appropriate way,” Gimpel says. “Don’t burden them with too many facts. It’s good to start talking [early] about the uncertainty of not knowing if they have it and how it will progress.”
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Christian Hanna, MD, assistant professor of pediatrics, pediatric nephrologist, Mayo Clinic.
Charlotte Gimpel, MD, Division of Pediatric Nephrology, Medical Center -- University of Freiburg, Germany.
PKD Foundation: “Parents of children with PKD.”
Advances in Chronic Kidney Disease: “The Spectrum of Polycystic Kidney Disease in Children.”
PKD Charity: “Symptoms and testing in children.”
Tufts Medical Center: “FDA approval of kidney drug ‘a game changer’ for PKD patients.”
Current Opinion in Pediatrics: “Autosomal dominant polycystic kidney disease in children.”
Nature Reviews Nephrology: “International consensus statement on the diagnosis and management of autosomal dominant polycystic kidney disease in children and young people.”