Genes may be to blame for cerebral palsy

Scientists have uncovered strong evidence for genetic causes of cerebral palsy - the most common cause of physical disability in children - that turns experts' understanding of the condition on its head.
Cerebral palsy has historically been considered to be caused by factors such as birth asphyxia, stroke and infections in the developing brain of babies.
The new study from The Hospital for Sick Children (SickKids) and the Research Institute of the McGill University Health Centre (RI-MUHC) could have major implications on the future of counselling, prevention and treatment of children with cerebral palsy.
"Our research suggests that there is a much stronger genetic component to cerebral palsy than previously suspected," said lead study author Dr Maryam Oskoui, Paediatric neurologist at The Montreal Children's Hospital (MCH) of the MUHC, and co-director of the Canadian Cerebral Palsy Registry.

"How these genetic factors interplay with other established risk factors remains to be fully understood. For example, two newborns exposed to the same environmental stressors will often have very different outcomes.
"Our research suggests that our genes impart resilience, or conversely a susceptibility to injury," said Oskoui, also an Assistant Professor in the Department of Paediatrics and Department of Neurology and Neurosurgery at McGill University.

Children with cerebral palsy have difficulties in their motor development early on, and often have epilepsy and learning, speech, hearing and visual impairments.
Genetic testing is not routinely done or recommended, and genetic causes are searched for only in rare occasions when other causes cannot be found.

The research team performed genetic testing on 115 children with cerebral palsy and their parents from the Canadian Cerebral Palsy Registry, many of which had other identified risk factors.
They found that 10 per cent of these children have copy number variations (CNVs) affecting genes deemed clinically relevant.
CNVs, which are found in less than one per cent of people, are structural alterations to the DNA of a genome that can be present as deletions, additions, or as reorganised parts of the gene that can result in disease.
"In light of the findings, we suggest that genomic analyses be integrated into the standard of practise for diagnostic assessment of cerebral palsy," said principle investigator of the study, Stephen Scherer, Director of The Centre for Applied Genomics (TCAG) at SickKids.

The study also demonstrates that there are many different genes involved in cerebral palsy.
"It's a lot like autism, in that many different CNVs affecting different genes are involved which could possibly explain why the clinical presentations of both these conditions are so diverse," said Scherer.
The study was published in the journal Nature Communications.