Molecular mapping of alzheimer‐type dementia in Down's syndrome

TLDR

Previous research has linked Alzheimer’s disease to the amyloid precursor protein (APP) gene on chromosome 21. We report a 78‑year‑old woman with Down’s syndrome and partial trisomy 21 (46,XX,rec(21)dup q, inv(21)(p12q22.1)). Neuropsychological, MRI, and neuropathological assessment found no Alzheimer’s disease, and the presence of only two APP copies in this partial trisomy 21 case supports the hypothesis that AD is linked to trisomy of proximal chromosome 21q.

Abstract

Previous research has hypothesized an association between Alzheimer's disease and the amyloid precursor protein (APP) gene found on chromosome 21. We report the case of a 78-year-old woman with Down's syndrome with partial trisomy 21 [46,XX,rec(21)dup q, inv(21) (p12q22.1)]. No evidence of Alzheimer's disease was found on neuropsychological, magnetic resonance imaging, and neuropathological assessment. The gene sequence for APP was present in only two copies. This case further supports the hypothesis that Alzheimer's disease is associated with trisomy for proximal chromosome 21q, including the APP gene.