Harper and his colleagues performed MRI brain scans on 12 children with CCHS and compared their scans to those of 28 healthy children matched by age and gender.
"We were startled to see severe tissue injury in multiple regions of the brains of children with CCHS," said Dr. Rajesh Kumar, first author and UCLA neurobiology researcher. "This damage prevents different parts of the brain from communicating with each other and blocks the nervous system from responding to involuntary reflexes."
Located primarily on the right side of the brain, the damage proved extensive. Tissue loss centered in the brain's emotion areas, which may explain the children's lack of fear to the feeling of suffocation. Damage also appeared in the anterior cingulate, which helps regulate cardiovascular function, blood pressure, heart rate and pain. This region also is involved in recognizing the urge to urinate.
The basal forebrain showed damage, as well. This area contains sensors for carbon dioxide, regulates thirst and body temperature, and plays a role in maintaining sleep.
"Now that we know where the damage exists, scientists can focus on new strategies to help the brain compensate for the injury," said Harper. "For example, we may be able to inject injured areas with nerve growth factors to stimulate the regrowth of lost nerve fibers and recover some functions."
At least 70 percent of CCHS children tested possess a mutation of PHOX2B, a gene related to brain structures that control blood vessel diameter. Harper hypothesizes that the mutated gene prevents normal development of these regions, resulting in narrowing of the blood vessels and inadequate blood flow to the brain sites that control breathing
"We think that insufficient blood flow starves cells of oxygen in the brain structures that regulate breathing," said Harper. "The breathing disorder results from the brain's inabi
Contact: Elaine Schmidt
University of California - Los Angeles