Causes and Types of Amyloidosis
Amyloidosis occurs when abnormal proteins misfold, become sticky, and collect in tissues where they don’t belong. Amongst the causes and types of amyloidosis, the exact cause depends on the type of amyloidosis, each with its own triggers, risk factors, and disease process.
1. AL (Light Chain) Amyloidosis
- Most common form in developed countries
- Caused by abnormal plasma cells in the bone marrow that produce misfolded immunoglobulin light chains
- Closely related to blood cancers like multiple myeloma
- Often affects the heart, kidneys, liver, and nerves
2. AA (Secondary) Amyloidosis
- Caused by a chronic inflammatory condition like:
- Rheumatoid arthritis
- Tuberculosis (still prevalent in parts of South Africa)
- Chronic infections or inflammatory bowel disease
- The liver produces a protein called serum amyloid A, which builds up in organs
- Commonly affects the kidneys, liver, and spleen
3. Hereditary (Familial) Amyloidosis
- Inherited condition caused by a mutation in genes like TTR (transthyretin)
- Passed from parent to child in an autosomal dominant pattern
- Typically affects the nerves and heart
4. Dialysis-Related Amyloidosis
- Occurs in people undergoing long-term haemodialysis
- Caused by accumulation of beta-2 microglobulin, which isn’t cleared properly during dialysis
- Affects bones, joints, and tendons
Risk Factors Across All Types
- Older age
- Male gender (more commonly affected)
- Family history (in hereditary cases)
- Chronic inflammatory or infectious disease
- Long-term dialysis (10+ years)
Understanding the type of amyloidosis is crucial because treatment varies widely. The next step in care involves proper diagnosis — which is often delayed due to non-specific symptoms.
👉 [Next: Diagnosis of Amyloidosis]
