Determination of Haptoglobin Genotype in an Iranian Population with Idiopathic Generalized Epilepsy

Background: Haptoglobin (Hp) is a plasma α۲-sialoglycoprotein that contains alpha and beta chains. It displays in three common phenotypes, Hp۱-۱, Hp۲-۱, and Hp۲-۲. Proteins expressed by polymorphic genes have grossly different molecular sizes resulting in different diffusion rates in the brain. Haptoglobin expressed by the Hp۲-۲ genotype has lower hemoglobin-binding capacity than Hp۱-۱ or Hp۲-۱ and is associated with idiopathic generalized epilepsy. Methods: To determine polymorphism in haptoglobin genes in patients with idiopathic generalized tonic-clonic seizures, ۴۲ men, ۴۲ women, and ۵۰ controls were selected for this study. Genomic DNA was extracted from blood and studied by polymerase chain reactions (PCR). Results: The amplified fragments for the Hp۱-۱ and Hp۲-۲ genotypes were ۱۷۵۷ and ۳۴۸۱ base pairs (bp) respectively, and the Hp۲-۱ genotype had both fragments, in addition to a ۳۴۹-bp fragment. The distribution of the three major Hp phenotypes in epilepsy patients was ۲۸.۶ (۱-۱), ۳۸.۱ (۲-۱), and ۳۳.۳% (۲-۲) in the men, and ۳۱ (۱-۱), ۴۰.۵ (۲-۱), and ۲۸.۶% (۲-۲) in the women. The distribution of Hp genotypes in controls was ۲۲ (۱-۱), ۴۰ (۲-۱), and ۳۸% (۲-۲). Conclusion: We show that all Hp genotypes participate in idiopathic generalized epilepsy.