Necrotizing autoimmune myopathy (NAM) is a relatively common form of myositis and is diagnosed based on the positivity of autoantibodies to HMGCR and/or SRP protein. It is frequently associated with exposure, more or less prolonged, to statins. American researchers have demonstrated a significantly higher prevalence of the disease in native American populations:
- an initial epidemiological investigation among Arizona Amerindians exposed to statins had already attracted attention, with 0.3% of them having developed NAM;
- a second study conducted in the Navajo Indian community produced similar figures, i.e. a prevalence 150 times higher than that observed in the general population;
- predisposing factors, particularly in relation to the HLA system, could be involved but have not yet been studied.