Causes and Risk Factors for Myopathy
Inheritable myopathies are caused by a genetic defect. The most common muscular dystrophies, Duchenne MD and Becker MD, result from a genetic defect on the X chromosome.
Risk factors for other types of myopathy include the following:
- Autoimmune disorders (e.g., myasthenia gravis, scleroderma, thyroiditis)
- Endocrine disorders (e.g., Cushing syndrome, hypothyroidism, hyperthyroidism, Addison disease)
- Exposure to toxins (e.g., herbicides, insecticides, flame retardant chemicals)
- Infection (e.g., HIV, Lyme disease, trichinosis)
- Vitamin D deficiency, vitamin E or A toxicity
- Medication (e.g., some antihistamines, long-term corticosteroid use)
- Metabolic disorder (e.g., glycogen and lipid storage diseases)
