New study shows genetic variations are a factor in 20 per cent of hemiplegic CP cases.
|What was thought to be an almost entirely environmental disorder has a significant genetic component. – Stephen Scherer, Hospital for Sick Children.|
By Ainslie Cruickchank, Toronto Star August 8, 2017
Researchers say genetic testing should be standard practice when diagnosing cerebral palsy after a new study found that genetic variations could be a factor in hemiplegic cerebral palsy, the most common form of the motor disability.
Standardizing a genetic workup for children with cerebral palsy, though, would depend on government funding.
“There should be genetic testing that happens as soon as possible; that’s the take home message in this study,” said Stephen Scherer, director of the Centre for Applied Genomics at SickKids and one of the authors of the study, with researchers at Holland Bloorview Kids Rehabilitation Hospital and the Hospital for Sick Children.
For families, genetic testing could help explain why their child developed cerebral palsy. For researchers, it offers new directions for research aimed at preventing and treating the condition, which affects three out of every 1,000 children born in Canada each year.
“The impact of this I think is going to be very, very significant,” Scherer said.
Sitting in the kitchen of his east-end home, Julian Cappelli, 16, is wearing a red Toronto FC T-shirt. Soccer’s his favourite sport and TFC is his favourite team.
Julian has quadriplegic cerebral palsy, which affects all four of his limbs. His family received that diagnosis when he was one year old. Julian said if he had the chance to have genetic testing done, he’d take it. Even 15 years later, he wants to know why he has a motor condition that, for him, means he won’t get the chance to try for a professional soccer career.
His mom, Donna, doesn’t spend much time anymore wondering why he has cerebral palsy. “We’re kind of just moving forward and dealing with what we have,” she said.
But that doesn’t mean she’s not excited about the new research. She is.
She remembers what it was like 15 and 16 years ago, wanting answers.
“It was so overwhelming and you do want to know: Why did this happen? Was it something that you did?
“It’s good to see that they’re still looking into the reasons why this is happening and trying to help prevent it and make these kids’ lives better,” she said.
Cerebral palsy is the most common physical disability in children, said Dr. Darcy Fehlings, a senior clinician scientist at Holland Bloorview specializing in cerebral palsy research and another of the study’s authors.
Although it is a permanent disability that affects children’s motor movements, it manifests itself differently in every child. In some cases, children may have difficulty using their hands or walking. In other cases, they may have trouble communicating or might need to use a wheelchair.
Though cerebral palsy is often thought to be caused when a baby doesn’t get enough oxygen before, during or after birth, causing damage to their brain or other organs, by stroke or infection in a child’s brain, researchers found a significant genetic link in hemiplegic cerebral palsy, which affects only one side of the body.
The study, published in the Genetics in Medicine journal outlines the results of DNA analysis on 97 children with hemiplegic cerebral palsy and their parents compared with more than 10,000 population control samples.
The researchers found that structural variations to the DNA that affect the genes for brain development and function were factors in 20 per cent of hemiplegic cerebral palsy cases and probably the major cause in five per cent of cases.
“We didn’t even look for this before,” Scherer said. “In retrospect, we should have.”
Diagnosing cerebral palsy can be difficult, especially in children, who aren’t fully developed. In about 10 per cent of cases, children diagnosed with cerebral palsy may actually have a different disorder, he said. A genetic workup can help confirm the diagnosis and make sure the best treatment plan is developed.
In a statement, a spokesperson for the Ministry of Health and Long-Term Care said the ministry recognizes the importance of genetic testing in providing patient care.
“Generally, with new or emerging tests, the test would undergo evidence-based evaluation that would guide decisions whether or not the test is used as part of routine standard of care, and making the best use of public healthcare resources.”
Genetic testing is already used to help diagnose and develop treatment for cystic fibrosis and muscular dystrophy. More recently, it is being used to help diagnose and develop treatment for autism spectrum disorder.
“There’s way more data here than we had in our early autism studies,” Scherer said.
Source Toronto Star
De novo and rare inherited copy-number variations in the hemiplegic form of cerebral palsy, Zarrei M, Fehlings DL, Mawjee K, Switzer L, Thiruvahindrapuram B, Walker S, Merico D, Casallo G, Uddin M, MacDonald JR, Gazzellone MJ, Higginbotham EJ, Campbell C, deVeber G, Frid P, Gorter JW, Hunt C, Kawamura A, Kim M, McCormick A, Mesterman R, Samdup D, Marshall CR, Stavropoulos DJ, Wintle RF, Scherer SW. Genet Med. 2017 Aug 3. doi: 10.1038/gim.2017.83. [Epub ahead of print]
Clinically relevant copy number variations detected in cerebral palsy, Oskoui M, Gazzellone MJ, Thiruvahindrapuram B, Zarrei M, Andersen J, Wei J, Wang Z, Wintle RF, Marshall CR, Cohn RD, Weksberg R, Stavropoulos DJ, Fehlings D, Shevell MI, Scherer SW. Nat Commun. 2015 Aug 3;6:7949. doi: 10.1038/ncomms8949.
Canadian study identifies genetic link to cause of cerebral palsy in The Hospital for Sick Children (SickKids)
Cerebral palsy linked to genetic anomalies in CBC News
Cerebral palsy may have genetic causes, Canadian study suggests in The Globe and Mail