This work involved collaboration with investigators at the Robert Wood Johnson Medical School, of the University of Medicine and Dentistry of New Jersey, and was led by Dr. Paola Leone and a group of 16 investigators and surgeons.
The children have Canavan disease, characterized by spongy degeneration of the brain's white matter. The disease affects the growth of the fatty myelin sheath insulating nerve fibers.
Canavan disease symptoms appear in early infancy and progress rapidly. These may include mental retardation, loss of previously acquired motor skills, feeding difficulties, abnormal muscle tone (floppiness or stiffness), poor head control and megalocephaly (abnormally enlarged head). Paralysis, blindness or hearing loss also may occur.
There is no cure for Canavan disease or a standard course of treatment other than symptomatic and supportive. Prognosis is poor; victims usually die before age 10.
"Children with Canavan disease have a mutation in one of their genes, causing a deficiency of an enzyme responsible for removing cellular waste," said Dr. R. Jude Samulski, professor of pharmacology at UNC's School of Medicine and director of the Gene Therapy Center. "In this disease, waste product builds up, causing brain cells to die."
Absolutely nothing can be done to prevent disease progression, said Samulski, which is why the objective was to place a gene into the brain that would express the missing enzyme.
The therapy received by the children uses a genetically altered adeno-associated virus, or AAV, to deliver genes into the body. Samulski, a pioneer in AAV research, said he chose to study and develop altered AAV for several reasons, including its potential for fewer toxic effects than that
Contact: Leslie Lang
University of North Carolina School of Medicine