<prompt> Defect in Amyloid protein folding occurs in:Alzheimer diseaseCreutzfeldt-Jakob diseaseScrapie diseaseBovine spongiform encephalopathy BSE  <response>: PROTEIN MISFOLDING AND DISEASES- 1 Amyloidosis - Amyloids is used to refer to the altered proteins with beta-sheets that accumulate in the body, paicularly in the nervous system Alzheimers disease is a neurodegenerative disorder Accumulation of beta amyloid. Other example of amyloidosis:- Type Protein Implicated Primary Principally light chains of immunoglobulins Secondary Serum amyloid A SAA Familial Transthyretin; others:- apolipoprotein A-1, Cystain C, fibrinogen, gelsolin, Lysozyme Alzheimers disease Amyloid b peptide see Chapter 57, case no. 2 Dialysis - related b2 - microglobulin 2 Prion disease - Etiology:-Proteinaceous infectious agents No change in 1o structures and post translation modification Change in 3D structures major change is replacement of alpha helix by beta sheets Can act as template to conve non-infectious proteins with cl-helices to infectious forms Example - Transmissible spongiform encephalopathies TSEs and Creutzfeldt Jakob disease in humans. Scrapie disease - sheep Bovine spongiform encephalopathy popularly known as mad cow disease in cattle 