Dementia due to Huntington disease

Definition

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.

Coding note

This category should never be used in primary tabulation. The codes are provided for use as supplementary or additional codes when it is desired to identify the presence of dementia in diseases classified elsewhere. When dementia is due to multiple aetiologies, code all that apply.

Inclusions

• Dementia in Huntington chorea

Also indexed as

Nearby in Dementia due to diseases classified elsewhere

• 6D85.0Dementia due to Parkinson disease
• 6D85.2Dementia due to exposure to heavy metals or other toxins
• 6D85.3Dementia due to human immunodeficiency virus
• 6D85.4Dementia due to multiple sclerosis
• 6D85.5Dementia due to prion disease
• 6D85.6Dementia due to normal pressure hydrocephalus
• 6D85.7Dementia due to injury to the head
• 6D85.8Dementia due to pellagra