Genetic risk factors associated with lipid‐lowering drug‐induced myopathies
Medical College of Wisconsin, Milwaukee, Wisconsin, United States Muscle & Nerve
(Impact Factor: 2.28).
08/2006; 34(2):153 - 162. DOI: 10.1002/mus.20567
Lipid-lowering drugs produce myopathic side effects in up to 7% of treated patients, with severe rhabdomyolysis occurring in as many as 0.5%. Underlying metabolic muscle diseases have not been evaluated extensively. In a cross-sectional study of 136 patients with drug-induced myopathies, we report a higher prevalence of underlying metabolic muscle diseases than expected in the general population. Control groups included 116 patients on therapy with no myopathic symptoms, 100 asymptomatic individuals from the general population never exposed to statins, and 106 patients with non–statin-induced myopathies. Of 110 patients who underwent mutation testing, 10% were heterozygous or homozygous for mutations causing three metabolic myopathies, compared to 3% testing positive among asymptomatic patients on therapy (P = 0.04). The actual number of mutant alleles found in the test group patients was increased fourfold over the control group (P < 0.0001) due to an increased presence of mutation homozygotes. The number of carriers for carnitine palmitoyltransferase II deficiency and for McArdle disease was increased 13- and 20-fold, respectively, over expected general population frequencies. Homozygotes for myoadenylate deaminase deficiency were increased 3.25-fold with no increase in carrier status. In 52% of muscle biopsies from patients, significant biochemical abnormalities were found in mitochondrial or fatty acid metabolism, with 31% having multiple defects. Variable persistent symptoms occurred in 68% of patients despite cessation of therapy. The effect of statins on energy metabolism combined with a genetic susceptibility to triggering of muscle symptoms may account for myopathic outcomes in certain high-risk groups. Muscle Nerve, 2006
Available from: Md Ashraful Alam
- "Due to the statin therapy, genomic variation has been found in COQ2 gene which encoding para-hydroxybenzoate-polyprenyl transferase for CoQ10 biosynthesis . Another report suggests that statins may affect energy metabolism (Carnitine palmitoyltransferase II deficiency) combined with a genetic susceptibility triggering myopathic outcomes in certain high-risk patients . "
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ABSTRACT: Co-enzyme Q10 (Co-Q10) is an essential component of the mitochondrial electron transport chain. Most cells are sensitive to co-enzyme Q10 (Co-Q10) deficiency. This deficiency has been implicated in several clinical disorders such as heart failure, hypertension, Parkinson’s disease and obesity. The lipid lowering drug statin inhibits conversion of HMG-CoA to mevalonate and lowers plasma Co-Q10 concentrations. However, supplementation with Co-Q10 improves the pathophysiological condition of statin therapy. Recent evidence suggests that Co-Q10 supplementation may be useful for the treatment of obesity, oxidative stress and the inflammatory process in metabolic syndrome. The anti-inflammatory response and lipid metabolizing effect of Co-Q10 is probably mediated by transcriptional regulation of inflammation and lipid metabolism. This paper reviews the evidence showing beneficial role of Co-Q10 supplementation and its potential mechanism of action on contributing factors of metabolic and cardiovascular complications.
Available from: Shalini Selvarajah
- "Some researchers have proposed that a synergistic interaction between genetic and
pharmacologic nuances might be a possible mechanism of statin myopathy.54 It has been found that statin-induced
myopathy is associated with a single-nucleotide polymorphism with intron 11 of the
SLCOIBI gene on chromosome 12.55 "
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ABSTRACT: Statins have demonstrated substantial benefits in supporting cardiovascular health. Older
individuals are more likely to experience the well-known muscle-related side effects of
statins compared with younger individuals. Elderly females may be especially vulnerable to
statin-related muscle disorder. This review will collate and discuss statin-related
muscular effects, examine their molecular and genetic basis, and how these apply
specifically to elderly women. Developing strategies to reduce the incidence of
statin-induced myopathy in older adult women could contribute to a significant reduction
in the overall incidence of statin-induced muscle disorder in this vulnerable group of
patients. Reducing statin-related muscle disorder would likely improve overall patient
compliance, thereby leading to an increase in improved short- and long-term outcomes
associated with appropriate use of statins.
Available from: Lisa Christopher-Stine
- "The finding of RYR1 disease-causing mutations and variants in individuals with severe and mild statin myopathy and none in the statin-tolerant control group suggests that RYR1 mutations and selected variants should be added to the existing list of associations with risk for mild and severe statin myopathy . Only 34 variants in RYR1 were analyzed in this study of which only 18 were proven to be disease-causing according to the European Malignant Hyperthermia Group (www.emhg.org). "
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ABSTRACT: Malignant hyperthermia (MH) is a pharmacogenetic, autosomal dominantly inherited disorder of skeletal muscle triggered by volatile anesthetics and infrequently by extreme exertion and heat exposure. MH has variable penetrance with an incidence ranging from 1 in 5000 to 1 in 50,000-100,000 anesthesias. Mutations in the ryanodine receptor gene, RYR1, are found in 50-70% of cases. We hypothesized that a portion of patients with drug-induced muscle diseases, unrelated to anesthesia, such as severe statin myopathy, have underlying genetic liability that may include RYR1 gene mutations. DNA samples were collected from 885 patients in 4 groups: severe statin myopathy (n=197), mild statin myopathy (n=163), statin-tolerant controls (n=133), and non-drug-induced myopathies of unknown etiology characterized by exercise-induced muscle pain and weakness (n=392). Samples were screened for 105 mutations and variants in 26 genes associated with 7 categories of muscle disease including 34 mutations and variants in the RYR1 gene. Disease-causing mutations or variants in RYR1 were present in 3 severe statin myopathy cases, 1 mild statin myopathy case, 8 patients with non-drug-induced myopathy, and none in controls. These results suggest that disease-causing mutations and certain variants in the RYR1 gene may contribute to underlying genetic risk for non-anesthesia-induced myopathies and should be included in genetic susceptibility screening in patients with severe statin myopathy and in patients with non-statin-induced myopathies of unknown etiology.
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