Cerebral palsy (CP), a relatively common condition that limits a person’s ability to move, could be a genetic disorder.
CP has traditionally been thought of as being brought on by a lack of oxygen during birth, but researchers from Boston Children’s Hospital suggest that as many as one-quarter of children with the disease have a genetic condition.
The research was published this week in the journal Annals of Clinical and Translational Neurology.
“In cerebral palsy, the first thing that comes to many physicians’ minds is birth injury or asphyxia,” Saddharth Srivastava, a neurologist at Boston Children’s Hospital said in a statement. “That idea has become pervasive, in both neurology and orthopedics training and among the general public.”
There can be a sense of guilt in families with children diagnosed with CP, a feeling that if something had happened differently, the child would not have the disorder, Srivastava says.
Srivastava says one mother of a child with CP told researchers she was relieved of more than 30 years of guilt.
“Many families felt they finally had a sense of closure,” Srivastava says.
Researchers were able to determine which genes were causing CP with the Children’s Rare Disease Cohorts genomic initiative. They sequenced the DNA of 50 people with an average age of 10.
Of the 50, 20 had a known risk for CP, which includes lack of oxygen at birth or a brain bleed, 24 had no known risk to CP, and five met the criteria for having CP and had a deteriorating condition. Cerebral palsy is not a progressive disease, meaning it does not normally get worse over time.
The DNA sequencing identified genetic variants in 13 patients, or 26 per cent. The most significant group was those with deteriorating conditions, known as “CP masqueraders” in the study. The gene mutations were identified in three CP masqueraders, or 60 per cent of the group’s total.
An additional three patients were identified in the risk factor group.
“These three patients are particularly intriguing,” Maya Chopra, study co-author says. “Could genetic disorders have made them more vulnerable to early brain injury? We have much to learn about the interplay between rare gene variants and perinatal events in the development of CP.”
In the past, clinics have diagnosed CP in children with muscle tightness or developmental delay without looking into the root cause. Benjamin Shore, co-director of the Cerebral Palsy and Spasticity Center, says the study is exciting and opens the door for properly diagnosing patients going forward.
“We can now investigate these causes with much more detail,” Shore says. “ I hope in the future we can provide genetic diagnoses for many more children, particularly CP masqueraders. This research is just the tip of the iceberg.”
Other conditions have been identified using genetic sequencing before. A study that monitored epilepsy, in particular, has quite a bit in common with the CP study.
Epilepsy was identified as having a correlation with genes decades ago, but the way the two conditions’ sequences were monitored and discovered seems familiar, Annapurna Poduri, co-author of the study and director of the Epilepsy Genetic Program says.
“We now have the scientific knowledge to pursue a precise diagnosis for children with CP that is not just descriptive, but that provides answers and may open a door to treating some of the underlying conditions we uncover,” Poduri says. “With precision diagnosis will come precision treatments for more and more children with CP, epilepsy, and other neurodevelopmental disorders.”