Genetic predisposition to atorvastatin-induced myopathy: a case report

The major clinical complication of statins is a variety of muscle complaints ranging from myalgia to rhabdomyolysis. There is growing evidence that carriers of genetic polymorphisms in the enzymes and transporters implicated in statin disposition, particularly the SLCO1B1 gene, are at increased risk of myotoxicity. Our objective is to report on two cases of statin-induced myopathy occurring in a family with two patients who are carriers of the loss of function SLCO1B1 genetic variant and to briefly review the related literature.

Patient 1, a 48-year-old man with history of coronary artery disease, experienced rapidly evolving muscle pain and weakness of the extremities during treatment with atorvastatin 40 mg. Patient 2, a 65-year-old man, father of patient 1, had symptoms similar to those of his son after 2 weeks' treatment with the same statin. Atorvastatin was stopped in both cases, and symptoms resolved. On the basis of family relationship between the two patients, it was possible to hypothesize a genetic basis for the myopathy. Genotyping showed the patients to be carriers of the rs4363657 polymorphism of SLCO1B1 gene.

The two cases reported here and the brief literature review emphasize the impact of genetic factors on the risk of myopathy with statins. Although genotyping all patients before initiating therapy is not recommended at present, pharmacogenetic testing may be useful for new patients who have a family history of statin-induced myopathy.