Huntington’s disease

About 90% of HD diagnoses based on the typical symptoms and a family history of the disease are confirmed by genetic testing to have the expanded trinucleotide repeat that causes HD. Most of the remaining are called huntington’s disease-like disorders. Most of these other disorders are collectively labelled HD-like (HDL).
HD may affect the individual’s judgment, memory, and other cognitive functions. Early signs might include having trouble driving, learning new things, remembering a fact, answering a question, or making a decision. Some may even display changes in handwriting.
Discovery of the HD gene has led to a less expensive, scientifically simpler, and far more accurate presymptomatic test that is applicable to the majority of at-risk people. The new test uses CAG repeat length to detect the presence of the HD mutation in blood. This is discussed further in the next section.