Renal amyloidosis pathophysiology

The kidney is the most involved organ in systemic amyloiosis. Suggested mechanisms of renal involvement include abnormal protein production or hereditary mutation.

• In systemic amyloidosis (AL/AH/AHL is much more common than AA) kidney is the most frequently involved organ.^[1]
• In renal amyloidosis, the mechanisms of amyloidogenesis may include:^[2]
  • Abnormal protein production
  • Overproduction wild-type proteins
  • Decreased excretion of wild-type proteins
  • Hereditary mutation
• In multiple myeloma, the cast nephropathy in distal tubules of nephrons results in renal impairment and deposition of AL amyloid protein in glomeruli can cause massive fibrillar involvement.^[3]

Hereditary amyloidosis due to amyloidogenic mutations:^[4]

• Transthyretin (TTR) (most common inherited mutation)
• Fibrinogen
• Apolipoprotein A1
• Apolipoprotein A2
• Lysozyme
• Gelsolin genes

• Alzheimer’s disease^[5]
• Down syndrome^[6]

On gross pathology, amyloid looks “waxy” or “lardaceous” ^[7]

Microscopic Pathology of all types of amyloid after Congo red dye staining include: ^[2]

• Orange-red appearance by normal light microscopy
• Apple-green birefringence upon polarized light

For more general information about amyloidosis, click here.

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