Chromosome - 1 SNP - rs1051740 Gene Name - EPHX1

Basic Information

Genotype Frequency
  • TT
  • CT
  • CC
  • --
Allele Frequency
  • T
  • C
  • --

SNP Expression Description

General SNP Description

The (C;C) genotype of this SNP is associated with severe hypersensitivity syndrome caused by carbamazepine in the presence of active human herpes virus (HHV) 6 or 7 infection along with HLA-A*3101 ( rs1061235 T allele). HLA-A*3101 (rs1061235 T allele) is a human leukocyte antigen that codes for a protein on cell surfaces that regulates the immune system. Carbamazepine Hypersensitivity Syndrome is a drug-induced, multi-organ syndrome that is potentially fatal. It is characterized by a fever, rash, hepatitis along with other multi-organ abnormalities. Carbamazepine is an anticonvulsant/antiepileptic or antiseizure drug that is used to treat epileptic seizures and trigeminal neuralgia, which is a chronic pain condition that affects the trigeminal nerve or the nerve that carries sensation from the face to the brain. This SNP is also associated with an increased risk of invasive ovarian cancer,  specifically the serous subtype, which means that this cancer arises from the cavity and produces a serous like fluid. In addition to that, this SNP has been associated with an increased risk for lung cancer in a Mexican Mestizo population. The C allele of this SNP is also associated with hypomethylation or decreased methylation of the ERCC3 gene, that means that there is a decrease in blood toxicity in a population exposed to benzene. Hypermethylation or increased methylation of ERCC3 gene and exposure to benzene is associated with an increase in blood toxicity and diseases like leukemia as well as other blood disorders. This gene encodes for microsomal epoxide hydrosolase, which is a xenobiotic metabolizing enzyme, meaning that this enzyme is involved in drug metabolism by modification of various drugs. This enzyme converts epoxides from degradation of aromatic compounds such as benzene, to trans-dihydrodiols which can be conjugated and excreted from the body. It functions in both the activation and detoxification of epoxides. Mutations in this gene could cause preeclampsia, a condition that causes high blood pressure and high concentration of protein in the urine, as well as epoxide hydrolase deficiency or increased epoxide hydrolase activity.


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