Which protein constitutes the paired helical filaments of the intracellular neurofibrillary tangles seen in Alzheimer's disease?
- A Amyloid precursor protein
- B Alpha-synuclein
- C Hyperphosphorylated microtubule-associated tau ✓
- D Ubiquitin
Correct answer: C. Hyperphosphorylated microtubule-associated tau
Explanation
Neurofibrillary tangles are composed of paired helical filaments made of hyperphosphorylated microtubule-associated tau protein, and their burden correlates better with clinical severity than amyloid plaque load. Alpha-synuclein is the protein of Lewy bodies in Parkinson disease and dementia with Lewy bodies, making option B the strongest distractor. Amyloid-beta derives from amyloid precursor protein but deposits extracellularly as neuritic plaques, not inside tangles.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.