Haptoglobin polymorphism in patients with preeclampsia

Background: Haptoglobin ( Hp) polymorphism has been associated with blood pressure regulation and essential hypertension. We investigated Hp polymorphism in patients with preeclampsia. Methods: A total of 60 Caucasian women with preeclampsia were prospectively followed from hospital admission until delivery. Serum Hp phenotypes 1-1, 2-1, and 2-2 were determined by starch gel electrophoresis and compared with those in 200 normotensive controls of the same geographic and ethnic origin. Blood pressure and laboratory markers ( serum uric acid, alanine aminotransferase, aspartate aminotransferase, platelet count, and 24- h proteinuria) were compared according to Hp phenotypes of pre-eclamptic women. Results: We found a higher Hp1 allele frequency in the preeclamptic group than in normotensive controls ( 0.517 vs. 0.400, p < 0.05). The Hp 1-1 phenotype was present in 28% of preeclamptic patients vs. 16% of the controls, with an odds ratio ( 95% CI) of 2.08 (1.05-4.08) for Hp 1-1 vs. the other Hp phenotypes. Diastolic (p < 0.005) and systolic (p < 0.05) blood pressure and proteinuria (p < 0.05) were highest in Hp 1-1 patients. Other laboratory markers were not significantly different between Hp phenotype subgroups. Conclusions: The Hp1 allele frequency was higher among preeclamptic patients and the Hp 1-1 phenotype was associated with more severe hypertension and proteinuria.