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.
Huntington disease is caused by a genetic defect on chromosome 4. The defect causes a part of DNA to occur many more times than it is supposed to. This defect is called a CAG repeat. Normally, this section of DNA is repeated 10 to 28 times.