Atrial Natriuretic Peptide Gene and Plasma Pro-ANP Concentration in Patients with Primary Open-Angle Glaucoma
Atrial natriuretic peptide (ANP) appears to have a physiological role in volume and pressure homeostasis. Increased cardiac expression and synthesis of ANP suggest a possible local paracrine function in a number of tissues including the eye. Therefore, the identification of genetic markers may prove to be an important advance in the diagnosis of patients with glaucoma and hypertension. Plasma pro-ANP concentration was measured in 30 clinical patients. A significant elevated level of prehormone was observed in glaucoma patients with blood hypertension. Also, the distribution of the genotypes and alleles of the HpaII, SmaI and ScaI polymorphisms of the ANP gene was examined in 20 hypertensive patients with glaucoma and normotensive controls. The frequencies of the ANP genotypes and alleles did not differ significantly between controls and hypertensive patients. PCR-RFLP (polymerase chain reaction—restriction fragment length polymorphism) analysis shows a T2238→C transition in three hypertensive patients within the stop codon leading to the translation of ANP with an additional arginine. In the current study we also searched for any alterations in the 5' proximal promoter region of the ANP gene (-595 bp - -384 bp) in 20 glaucoma patients with hypertension using PCR-based SSCP (single-strand conformation polymorphism) analysis. No significant alterations in the 5' proximal promoter region of the ANP gene were observed among hypertensive patients. The structure of the ANP hormone encoded gene suggests potential importance in various diseases, but the regulatory function of ANP in the eye requires further investigations.