The effect of catalase enzyme gene polymorphism A-21T (rs7943316) on epilepsy and its drug resistance after hypoxic ischemic brain injury

Background
Epilepsy is one of the most common serious neurological disorders, affecting more than 4% of all children. One of the most common conditions leading to epilepsy is hypoxic ischemic encephalopathy (HIE), which is a condition that occurs when the entire brain is deprived of an adequate oxygen supply. Catalase (CAT) is a major cytoplasmic antioxidant enzyme. Considering that the A-21T and C-262T polymorphisms in the promoter region of CAT are associated with the activity of promoter of the CAT, subsequently it may alter the risk of oxidative stress-related disorders. Therefore, polymorphism of the CAT gene can be a candidate marker of the risk of epilepsy.
Objective
The aim was to assess if antioxidant CAT gene polymorphism A-21T (rs7943316) contributes to susceptibility to epilepsy, susceptibility to epilepsy after neonatal HIE, susceptibility to epilepsy owing to other causes than neonatal HIE, resistance to antiepileptic medications in epileptic patients after HIE, and/or resistance to antiepileptic medications in epileptic patients owing to causes other than HIE.
Patients and methods
This cross-sectional case–control descriptive analytical study included 105 participants: 70 patients with epilepsy (divided into two groups according to the etiology of epilepsy) were compared with 35 age-matched and sex-matched healthy controls. The patients were recruited from neuropediatrics clinic in Fayoum University Teaching Hospital during a period extending from September 2017 till February 2018. All samples were subjected to genomic DNA analysis of catalase enzyme polymorphism A-21T (rs7943316) using real-time polymerase chain reaction-based method.
Results
This study showed that there was a statistically significant difference ( < 0.05) between patients with epilepsy due to HIE and controls regarding genotyping, where AA (wild genotype) was higher among controls, whereas AT (heterozygous mutant genotype) was higher among cases. Moreover, AT (heterozygous mutant genotype) and T allele were statistically significantly higher among epilepsy with HIE cases when compared with epilepsy without HIE ( < 0.001 and < 0.01, respectively). However, there was no statistically significant difference in CAT rs7943316 genotype and allele frequency when patients with epilepsy were stratified by drug resistance, electroencephalography, or sex.
Conclusion
Our study revealed that there was a significant link between CAT A-21T (rs7943316) single nucleotide polymorphism and susceptibility to epilepsy after neonatal HIE. CAT polymorphism does not influence the overall risk of drug resistance among participants with epilepsy after neonatal HIE or owing to other causes than HIE.