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. Definition. Huntington's disease is an inherited disease that causes the progressive breakdown (degeneration) of nerve cells in the brain. Huntington's disease has a broad impact on a person's functional abilities and usually results in movement, thinking (cognitive) and psychiatric disorders.
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.