<prompt> A chromosomal anomaly associated with Alzheimers dementia is:Trisomy 18Patau syndromeTrisomy 21Turners syndrome  <response>: Answer is C Trisomy 21 : Several genetic factors are known to play impoant roles in pathogenesis of at least some cases of Alzheimers disease. Trisomy 21 is one of them. Adults with trisomy 21 Downs consistently develop the Neuropathologic hallmarks of Alzheimers disease if they survive beyond age 40. 