Determination of haptoglobin genotype in an Iranian population with idiopathic generalized epilepsy.

Background: Haptoglobin (Hp) is a plasma α2-sialoglycoprotein that contains alpha and beta chains. It displays in three common phenotypes, Hp1-1, Hp2-1, and Hp2-2. Proteins expressed by polymorphic genes have grossly different molecular sizes resulting in different diffusion rates in the brain. Haptoglobin expressed by the Hp2-2 genotype has lower hemoglobin-binding capacity than Hp1-1 or Hp2-1 and is associated with idiopathic generalized epilepsy.

Methods: To determine polymorphism in haptoglobin genes in patients with idiopathic generalized tonic-clonic seizures, 42 men, 42 women, and 50 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 Hp1-1 and Hp2-2 genotypes were 1757 and 3481 base pairs (bp) respectively, and the Hp2-1 genotype had both fragments, in addition to a 349-bp fragment. The distribution of the three major Hp phenotypes in epilepsy patients was 28.6 (1-1), 38.1 (2-1), and 33.3% (2-2) in the men, and 31 (1-1), 40.5 (2-1), and 28.6% (2-2) in the women. The distribution of Hp genotypes in controls was 22 (1-1), 40 (2-1), and 38% (2-2).

Conclusion: We show that all Hp genotypes participate in idiopathic generalized epilepsy.