6D85.9
Dementia due to Down syndrome
Demência devida à síndrome de Down
CategoryDefinition
Dementia due to Down syndrome is a neurodegenerative disorder related to the impact of abnormal increased production and accumulation of amyloid precursor protein (APP) leading to formation of beta-amyloid plaques and tau tangles. APP gene expression is increased due to its location on chromosome 21, which is abnormally triplicated in Down syndrome. Cognitive deficits and neuropathological features are similar to those observed in Alzheimer disease. Onset is typically after the fourth decade of life with a gradual decline in functioning, and may impact 50% or more of individuals with Down syndrome.
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.
Diagnostic Criteria
- All diagnostic requirements for Dementia are met.
- Dementia is presumed to be attributable to Down syndrome, as demonstrated by neuropsychological test data, genetic testing, medical tests, and/or clinical history.
- Dementia Due to Down Syndrome is caused by abnormal increased production and accumulation of amyloid precursor protein (APP) leading to formation of beta-amyloid plaques and tau tangles. APP gene expression is increased due to its location on chromosome 21, which is abnormally triplicated in Down syndrome. Dementia Due to Down Syndrome may affect 50% or more of individuals with Down syndrome.
- Neurocognitive deficits and neuropathological features are similar to those observed in Alzheimer Disease.
- Onset is typically after the fourth decade of life and is often accompanied by a gradual decline in functioning.
Note: A diagnosis of LD40.0 Complete Trisomy 21 (Down syndrome) should also be assigned.
Index Terms
Dementia due to Down syndrome