The impact of SLCO1B1 single nucleotide polymorphism and non-genetic factors on statin-induced myopathy

Abstract

Abstract Funding Acknowledgements None. Background Statins, also known as HMG CoA Reductase Inhibitors, are a class of drugs considered the drug of choice for treating hypercholesterolemia. Statins are well tolerated; however, they may cause severe myopathy in 20% to 30% of patients, due to the individual variation regarding its efficacy and related adverse effects. Of these, comes the Single Nucleotide Polymorphism (SNP) T521C of the SLCO1B1 gene that encodes the protein involved in the trafficking of statins from the blood to hepatocytes which is called Organic Anion Transport Protein 1B1 (OATP1B1). The T521C single nucleotide polymorphism (SNP) results in a substitute of valine with alanine resulting in a decreased or lack of functional protein. Purpose The aim is to determine the frequency of the high-risk C allele and to define its impact on statin-induced myopathy in Syrian patients on statins. In addition to the non-genetic factors that may affect the ability to develop statin-induced myopathy. Methods This was an observational case-control study that had ethical approval from Damascus University (No.433/ 2020). The case group included 44 patients on statins who experienced myopathy, 18 patients who had increased creatinine kinase levels (CK), and 26 patients with normal CK levels, while the control group encompassed 56 patients who were taking statins and had no muscular adverse events. The DNA was extracted from each sample and then genotyped using standard sequencing of specific PCR products using a specific pair of primers. Results The age of patients in the case arm ranged between 27 and 84 years with an average ± SD of (58.2 ± 12.7 years), 70% of them were males. In comparison with (53.34 ± 12.4 years) in the control arm, 66% of them were males without a statistically significant differences (p=0.672, 0.057) respectively. The statin type and dose have a statistically non-significant effect, the average statin dose in the case arm and the control arm was 26.02 mg and 31.27 mg respectively (p=0.072). While the statin type treatment varied as 59% used atorvastatin and 39% used rosuvastatin in the case group compared with 71% used atorvastatin and 27% used rosuvastatin in the control group, without a statistically significant difference (p=0.252). The frequency of the C allele reaches 19.3% and is distributed in three genotypes: wild-type TT (68%), heterozygote TC (25%), and homozygote CC (7%) in the case arm, while it does not exceed 8% in the control arm with the absence of the CC genotype. Only a statistically significant difference was found in the frequency of the CC genotype between these two groups (p=0.047). Conclusion Our study is the first to identify the frequency of the 521T>C SNP of the SLCO1B1 gene in Syrian patients taking statins. Our data reveals a high prevalence of risk allele C in the patients who suffer from statin-induced myopathy with a statically significant difference from the control arm (p=0.026).