(NEW YORK) -- Scientists are hopeful that gene therapy may help patients suffering with Tay-Sachs -- an inherited neurological disease -- after disease progression was slowed in Jacob sheep, animals which naturally have the disease.
Tay-Sachs is caused by gene mutation and results in the absence or insufficient levels of the enzyme hexosamindase A, or hexo-A. Without it, a fatty substance, or lipids, accumulates in the cells, mostly in the brain. The disease comes in three forms: infantile, juvenile or adult onset.
It is an autosomal recessive disorder, which means each parent must carry the gene. Their children have a 25 percent chance of developing Tay-Sachs, 50 percent chance of being a carrier and a 25 percent chance of being free of that recessive gene.
Doctors say there can be great variations in the presentation of Tay-Sachs, even in the same family with the same mutations. Babies born with classic infantile Tay-Sachs appear normal at first, but by 3 or 4 years old, their nerve cells deteriorate and they eventually die. Those with the milder adult form of Tay-Sachs can lead full lives, despite their disability.
Now, science is getting closer to finding treatments for this devastating disease.
Dr. Edwin Kolodny, former department chair and now professor of neurology at New York University School of Medicine, and others are involved in the promising gene therapy studies involving first mice, then cats and now sheep. The researchers found that injecting genes into the brains of Jacob lambs doubled their life span.
Clinical trials on humans are set to begin by 2013, as soon as researchers can raise another $700,000 -- in addition to a grant from the National Institutes of Health -- to manufacture the vectors required to insert the genes into the body.
Copyright 2011 ABC News Radio