Dementia due to Huntington disease (Q40237)

Dementia due to Huntington disease occurs as part of a widespread degeneration of the brain due to a trinucleotide repeat expansion in the HTT gene, which is transmitted through autosomal dominance. Onset of symptoms is insidious typically in the third and fourth decade of life with gradual and slow progression. Initial symptoms typically include impairments in executive functions with relative sparing of memory, prior to the onset of motor deficits (bradykinesia and chorea) characteristic of Huntington disease.