Public release date: 16-May-2012 [ | E-mail | Share ]

Contact: John Pastor jdpastor@ufl.edu 352-273-5815 University of Florida

Using gene transfer techniques pioneered by University of Florida faculty, Taiwanese doctors have restored some movement in four children bedridden with a rare, life-threatening neurological disease.

The first-in-humans achievement may also be helpful for more common diseases such as Parkinson's that involve nerve cell damage caused by lack of a crucial molecule in brain tissue. The results are reported today (May 16) in the journal Science Translational Medicine.

The children in the study, who ranged in age from 4 to 6, inherited a rare disease known as aromatic L-amino acid decarboxylase deficiency, or AADC. Patients with AADC are born without an enzyme that enables the brain to produce the neurotransmitter dopamine. They generally die in early childhood.

In a phase 1 clinical trial led by Paul Wuh-Liang Hwu, M.D., of the National Taiwan University Hospital, surgeons used a delivery vehicle called an adeno-associated virus type 2 vector to transport the AADC gene into localized areas of the brains of three girls and a boy.

Before therapy, the children showed practically no spontaneous movement and their upper eyelids continually drooped. After receiving the corrective gene, the children gradually gained some head movement. Sixteen months afterward, the children's weight had increased, one patient was able to stand and the other three were able to sit up without support.

The study shows gene therapy that targets AADC deficiency is well-tolerated and leads to improved motor development and function, according to co-authors Barry Byrne, M.D., Ph.D., director of UF's Powell Gene Therapy Center, and Richard O. Snyder, Ph.D., director of UF's Center of Excellence for Regenerative Health Biotechnology. Both are members of the UF Genetics Institute.

"The children in this study have the most severe form of inherited movement disorder known, and the only treatments so far have been supportive ones," said Byrne, a pediatric cardiologist and associate chairman of the department of pediatrics in the College of Medicine. "It is gratifying to see it is possible to do something to help them, other than providing feeding tubes and keeping them safe. This absolutely opens the door to the possibility of even earlier treatment of neurological diseases by direct gene transfer, and has implications for Parkinson's disease, ALS and even cognitive diseases such as dementia when caused by gene defects."

The Powell Gene Therapy Center provided expertise to the Taiwanese physicians on treating the patients and engineering the corrective gene that spurs production of the absent AADC enzyme. UF's Center of Excellence for Regenerative Health Biotechnology manufactured the vector, packaging genetic material it received from Taiwan into virus particles that were purified, characterized and tested for sterility and stability before being shipped to the clinic for use in patients.

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Children with rare, incurable brain disease improve after gene therapy