The most common form of dementia in these patients is Alzheimer's disease (AD). Accumulation of beta-amyloid with plaques and neurofibrillary tangles is seen in the brains of almost all patients with Down's syndrome, often starting at a young age.
Risk factors for early onset of Alzheimer's disease may include:
(1) parents with Alzheimer's disease
(2) one or two apoE epsilon 4 alleles
(3) male gender
(4) estrogen deficiency (in women)
Clinical findings which may precede or accompany the onset of AD:
(1) depression
(2) seizures
(3) increased levels of beta-amyloid(1-42) in the plasma
Other forms of cognitive impairment may also occur, including:
(1) dementia with Lewy bodies (DLB), which is associated with psychosis
(2) depression with pseudodementia
(3) complications of head trauma
(4) medications
(5) vascular infarcts secondary to underlying cardiac disease
