Abstract

GENETIC POLYMORPHISM OF ANGIOTENSINOGEN GENE IN HIGH BLOOD PRESSURE

*Hassan Abdul Reza Fayyad and Ismail Hussein Aziz

ABSTRACT

Hypertension or high blood pressure a medical condition defined as arterial pressure elevated above 140/90 mmHg.[1] Hypertension is one of the most prevalent chronic disorders in the UK, affecting about 25% of the adult population.[2] We have statistics referring Iraqi Ministry of the year (2008-2013) that the number of patients infected with high blood pressure in Iraq was(3,184,348)infected .As it turned itself of Statistics said the number of infected people in Baghdad was(837,993)infected as in table(1).This disorder has an important role in the morbidity and mortality of heart and kidney disease patients.[3] Hypertension can be classified as either essential or secondary. While secondary hypertension is a result of another defined condition, affecting only 5% of hypertensive patients, Essential hypertension refers to hypertension of unknown cause. and comprises 95%of all cases It is believed that EH is a multifactorial and polygenic disease; it results from an interplay between environmental (such as diet rich in sodium, obesity alcohol, smoking, and stress), and genetic factors.[5-6] The renin-angiotensin system (RAS),plays an important role in the regulation of blood pressure.[7] Upon a decrease in blood pressure, renin is released mainly by juxtaglomerular cells and acts on angiotensinogen (AGT), cleaving off the decapeptide angiotensin-I (Ang I) . The latter is then converted by angiotensin-converting-enzyme (ACE) to angiotensin-II (Ang II), an octapeptide. Ang II is an active vasopressor which causes constriction of arteriolar smooth muscle.[8] In addition to its direct actions which lead to an increase in blood pressure, Ang II acts on the adrenal cortex to cause the release of the sodium-retaining hormone aldosterone. Angiotensinogen (AGT) gene located on chromosome 1q42-43, contains five exons spanning 13 kb Angiotensinogen (AGT) belongs to serpin gene superfamily and is expressed in liver, brain, heart, adipose tissue, vessel walls and kidneys.[9] Various single nucleotide polymorphisms (SNPs) have been identified in the AGT gene. One of these SNPs, A-20C, in promoter of the AGT gene, the A-20C mutation may also affect the transcription activity of AGT mRNA in humans and thereby alter the plasma AGT level.[10]

Keywords: Hypertension, The renin angiotensin system, AGT gene (A20-C).