La malattia di Alzheimer e la sindrome di Down: un infelice connubio

Introduction

People with Down's syndrome (DS) have an increased risk of developing Alzheimer's disease (AD) during middle age. Both disorders can present with a decline in cognitive skills and behavioral symptoms. Therefore, dementia, particularly in its early stages, can be difficult to diagnose in this population.

Materials and methods

We conducted a search of electronic databases for literature on the relationship between AD and DS. The key words used were: “Down syndrome”, “Alzheimer's disease”, “dementia”, and “mental retardation”.

Results

AD onset has been reported as early as age 30 in individuals with DS, and there is a dramatic increase in prevalence rates in older age groups. This trend reflects increased survival of persons with DS probably as a result of advances in medical treatment and improved living conditions. Even with careful clinical assessment, it can be very difficult to identify early symptoms of dementia when it is superimposed on a background of intellectual disability. The reasons include the wide intra-individual variability in cognitive functioning and difficulties involved in establishing baseline levels of the premorbid condition. Many frontal lobe-related symptoms usually associated with later stages of dementia in the general population are commonly seen in the early stage of the dementia that develops in adults with DS.

Discussion

After onset, the clinical symptoms of dementia progress rapidly in all subjects with DS. Research suggests that the presentation of dementia in people with DS may differ from that typical of AD in the general population. Early changes tend to involve personality and behaviour rather than memory. DS can be best understood as a complex syndrome of genetic origin that has protean neurobiological consequences and numerous clinical characteristics.