Lead author Dr. Maryam Oskoui, a pediatric neurologist at the Montreal Children's Hospital (MCH), says that the researchers are yet to understand how these genetic factors interplay with other established risk factors.
"For example, two newborns exposed to the same environmental stressors will often have very different outcomes," she explains. "Our research suggests that our genes impart resilience, or conversely a susceptibility to injury."
According to the Centers for Disease Control and Prevention (CDC), cerebral palsy is the most common motor disability in childhood. The disorder can affect movement, muscle tone and posture, often leading to unsteady walking, involuntary movements and floppy or rigid limbs.
A survey in 2008 found that 58.2% of children with cerebral palsy could walk independently. Around 11.3% could walk with a hand-held mobility device, while 30.6% had limited or no walking ability at all. Around 2 out of every 1,000 births are affected by the disorder.
Cerebral palsy has long been considered to be caused by factors such as infections and birth asphyxia that affect the developing brains of babies. As such, genetic testing is not routinely carried out among children with the disorder.
In light of the study's findings, however, the researchers suggest that genomic analyses should be integrated into standard practice in the assessment of cases of cerebral palsy.
Discovery could explain diverse clinical presentation of disorder
Using data from the Canadian Cerebral Palsy Registry, the researchers conducted genetic testing on 115 children with cerebral palsy and their parents - many of whom had other recognized cerebral palsy risk factors.
The researchers discovered that around 10% of the children had copy number variations (CNVs) affecting genes considered clinically relevant to the disorder. CNVs are structural changes to the DNA of a genome involving gains or losses of genetic material that can lead to disease.
Among the general population, these particular CNVs occur in less than 1% of people. "When I showed the results to our clinical geneticists, initially they were floored," reports principal investigator Dr. Stephen Scherer, director of The Centre for Applied Genomics (TCAG) at SickKids.
The researchers also found that there are several different genes involved in the development of cerebral palsy, which could explain why children can be affected by the disorder in a diverse range of ways in a similar manner toautism.
"Interestingly, the frequency of de novo, or new, CNVs identified in these patients with cerebral palsy is even more significant than some of the major CNV autism research from the last 10 years," Dr. Scherer adds. "We've opened many doors for new research into cerebral palsy."
Dr. Michael Shevell, chair of the Department of Pediatrics at MCH-MUHC, states that discovering the cause of a child's disability is an important step to be taken in managing it:
"Parents want to know why their child has particular challenges. Finding a precise reason opens up multiple vistas related to understanding, specific treatment, prevention and rehabilitation. This study will provide the impetus to make genetic testing a standard part of the comprehensive assessment of the child with cerebral palsy."
Last year, Medical News Today reported on the story of Ruby Hamilton, a young girl significantly affected by cerebral palsy, and how a computer and eye gaze technology have helped give Ruby a sense of independence.
