Dr. Nancy Wexler says the newest discovery on the origin of Huntington’s disease is a ‘fabulous experiment’ with ‘very promising’ results.  Wexler, of the Hereditary Disease Foundation, was part of the research team that discovered a toxic chemical reaction, called sumoylation, that occurs when the inherited gene for Huntington’s disease mixes with a particular molecule of the brain’s corpus striatum.  The research offers hope for more information on Alzheimer’s disease, too, which is quite similar to Huntington’s disease in the way it affects mental capabilities.

Huntington’s is a very rare disease, affecting only about 30,000 patients in the United States, but it strikes with devastating results.  When one parent carries the mutated gene that causes the disease, every child this parent has faces a 50/50 chance of inheriting it.  Symptoms usually begin when the child is in his or her late 30s or early 40s, disabilities soon follow, and death occurs ten or more years after onset of symptoms.

Although every cell in the body carries the mutated gene, it’s only brain cells that become affected.  As the cells of the corpus striatum, which controls movement, die off due to disease, the patient develops uncontrollable twitches and jerky movements that eventually make eating, speaking, and walking impossible.  Mental function declines, too.

The gene mutation was discovered in 1993 but, until now, medical science was unable to understand why damage occurs only in the brain, even though all other cells in the body carry the gene, too.

The research team, led by Dr. Solomon Snyder, Johns Hopkins University, found that problems begin when the mutated Huntington’s gene mixes with the Rhes molecule.  The molecule, of which only little is known, is found only in the brain’s striatum.

The research team suggests the brain may clump faulty proteins together as a means of saving itself from destruction.  These clumps, called aggregates, are associated with both Huntington’s and Alzheimer’s diseases.  In the case of Huntington’s, the Rhes molecule prevents the clumping and thus the brain’s ability to save itself.  One common theory is that the clumping activity destroys the brain but Snyder’s research indicates the problem may actually be the Rhes molecule.

Wexler says the next step is to find ways to block the molecule from mixing with the Huntington’s gene.  The key will be finding a way to remove or block it without causing an excess of side effects.

The latest issue of the journal, Science, carries full details.