Residents of the District of Columbia lack full democratic representation in the U. S. Senate or the U.S. House of Representatives. Representation in Congress is limited to a non-voting delegate to the House of Representatives and a shadow Senator.
Huntington's disease is a progressive brain disorder caused by a single defective gene on chromosome 4 â one of the 23 human chromosomes that carry a personâs entire genetic code. This defect is dominant, meaning that anyone who inherits it from a parent with Huntington's will eventually develop the disease.
Causes and symptoms. Huntington disease is caused by a defect in the HD gene (an inherited unit which contains a code for a protein), which is located on the short arm of chromosome 4. The gene codes for a protein called huntingtin, whose function is not known as of early 2005.