Therapies help pachygyria sufferers
July 19, 2011
By Emily Baer
Pachygyria is a neuronal migration disorder that results in too few gyri, or folds in the brain, according to Seattle Children’s pediatric neurologist Alexander Paciorkowski.
Isolated pachygyria means that only one part of the brain is affected; extensive pachygyria signifies that most of the brain is absent of gyri. The condition is closely related to lissencephaly, a term used to describe the condition of a brain that is completely smooth.
Pachygyria is classified as a rare condition. Neurologists and geneticists consider rare conditions to arise in less than 1 in 2,000 people. Though in most cases it is genetic, sometimes pachygyria can be caused by infection early in a pregnancy.
During fetal development, neurons must migrate from their place of origin deep inside the brain to their proper neural circuits near the brain’s surface. Neuronal migration, which can occur as early as the second month of gestation, is controlled by chemical signals. Neurons that settle outside of their designated locations cause the brain to develop structural abnormalities.
“A neuronal migration disorder is a disorder where the neurons do not migrate as they should,” Paciorkowski said. “Because the neurons are not showing up on the surface of the brain, the surface of the brain is not as developed as it should be and has fewer gyri. This is a shared finding of all neuronal migration disorders.”
The extent to which a person with pachygyria is affected depends on how absent the brain is from convulsions. Paciorkowski said that in most cases, people with pachygyria have moderate to severe developmental delay and epilepsy.
“In other cases, the person will be less impaired or handicapped. It’s very hard to predict,” he said. “People end up crawling and walking later than expected, and as they get older may require a more significant amount of repair.”
While people with pachygyria do not have a predetermined average life expectancy due to the variability of the condition’s extent, Paciorkowski said that the likelihood of a patient with the condition living a long life is getting better.
“I think what’s happened over the past couple decades is general medical care has gotten a lot better,” he said. “Many children who have developmental conditions are surviving much later.”
As for cures, none exist to fix the absence of gyri, but therapy can help those with pachygyria learn to walk and communicate.