Description

The SLCO1B1 genotype test helps assess an individual's genetic risk for statin-induced myopathy, a condition where statin medications (commonly used to lower cholesterol) cause muscle pain, weakness, and fatigue. The SLCO1B1 gene encodes a protein that helps the liver remove statins from the bloodstream. Certain genetic variations in this gene can lead to higher statin concentrations in the blood, increasing the risk of myopathy.

Key Genetic Factor:

  • rs4149056:
  • The C allele of this single nucleotide polymorphism (SNP) is associated with an increased risk of statin-induced myopathy. The Val174Ala (5 allele) is a loss-of-function allele that reduces the ability of the liver to remove statins efficiently, leading to higher concentrations of the drug in the blood. Individuals with this genetic variation have a higher likelihood of experiencing muscle-related side effects from statins.
  • SLCO1B1-Poor Function Genotype:
  • People with this genotype are at higher risk for myopathy, particularly when taking simvastatin. This risk is due to the reduced ability of the liver to clear statins, leading to increased drug levels in the bloodstream.

Recommendations for Statin Therapy Based on SLCO1B1 Genotype:

  • Consider an alternative statin to reduce the risk of myopathy.
  • Limit the dose of simvastatin to less than 20 mg per day, as higher doses increase the risk of side effects.
  • Avoid the 80 mg dose of simvastatin unless it has been well tolerated for at least 12 months.
  • Consider a lower dose of simvastatin to minimize the risk of myopathy in those with poor-function SLCO1B1 genotypes.

Other Factors Affecting Statin-Induced Myopathy:

  • Statin dose: Higher doses increase the risk.
  • Age: Older individuals may be more susceptible to side effects.
  • Drug interactions: Certain medications can interfere with statin metabolism.
  • Comorbidities: Pre-existing conditions like kidney or liver disease can increase the likelihood of myopathy.

Symptoms of Statin-Induced Myopathy:

  • Muscle pain
  • Weakness
  • Fatigue

Test Information:

  • Test Time: Results take approximately 14 business days, not including transportation time.
  • Fasting: Not required for this test.