What is Which chromosomal anomaly associated with alzheimer's dementia? and explain in detail?
Several genes play impoant pathogenic roles in at least some patients with Alzheimer's disease(AD). One is the APP gene on chromosome 21. Adults with trisomy 21 (Down syndrome) consistently develop the typical neuropathologic hallmarks of AD if they survive beyond age 40. Presenilin-1 (PS-1) is on chromosome 14 and encodes a protein called S182. Mutations in this gene cause an early-onset AD transmitted in an autosomal dominant, highly penetrant fashion. The Apo E gene on chromosome 19 is involved in the pathogenesis of late-onset familial and sporadic forms of AD. AD most often presents with an insidious onset of memory loss followed by a slowly progressive dementia over several years. Pathologically, atrophy is distributed throughout the medial temporal lobes, lateral and medial parietal lobes and lateral frontal coex. Microscopically, there are neuritic plaques containing A-beta, neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau filaments, and accumulation of amyloid in blood vessel walls in coex and leptomeninges. Clinical Manifestation begins with memory impairment and spreading to language and visuospatial deficits.The management of AD is challenging and gratifying, despite the absence of a cure or a robust pharmacologic treatment. Donepezil (target dose, 10 mg daily), rivastigmine (target dose, 6 mg twice daily or 9.5-mg patch daily), galantamine (target dose 24 mg daily, extended-release), memantine (target dose, 10 mg twice daily), and tacrine are the drugs presently approved by the Food and Drug Administration (FDA) for treatment of AD.Ref:Harrison's Internal Medicine, 18th Edition, Pages 3307, 3309, 3049