Huntington's disease is a genetic, progressive,
neurodegenerative disorder characterized by the gradual development of involuntary muscle movements affecting the hands, feet,
face, and trunk and progressive deterioration of cognitive processes and memory (dementia). Neurologic movement abnormalities
may include uncontrolled, irregular, rapid, jerky movements (chorea) and athetosis, a condition characterized by relatively
slow, writhing involuntary movements. Dementia is typically associated with progressive disorientation and confusion, personality
disintegration, impairment of memory control, restlessness, agitation, and other symptoms and findings. In individuals with
the disorder, disease duration may range from approximately 10 years up to 25 years or more. Life-threatening complications
may result from pneumonia or other infections, injuries related to falls, or other associated developments.
disease is transmitted as an autosomal dominant trait. The disease results from changes (mutations) of a gene known as "huntingtin"
located on the short arm (p) of chromosome 4 (4p16.3). In those with the disorder, the huntingtin gene contains errors in
the coded "building blocks" (nucleotide bases) that make up the gene's instructions. The gene contains abnormally long
repeats of coded instructions consisting of the basic chemicals cytosine, adenine, and guanine (CAG trinucleotide repeat expansion).
The length of the expanded repeats may affect the age at symptom onset. The specific symptoms and physical features associated
with Huntington's disease result from degeneration of nerve cells (neurons) within certain areas of the brain (e.g., basal
ganglia, cerebral cortex).
Credit to www.rarediseases.org