Dementia due to Down syndrome

Description

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.

Coding note from above levels

This category should only be used for primary tabulation, if the aetiology of the dementia is unknown. If the aetiology of the dementia is known code to the aetiology of the dementia for primary tabulation. When dementia is due to multiple aetiologies, code all that apply.

Exclusions from above levels

• 6A00 – Disorders of intellectual development
• 6D70 – Delirium
• http://id.who.int/icd/entity/1516623224 – Neurodevelopmental disorders