Identification of a polymorphic glutamic acid stretch in the alpha(2B)-adrenergic receptor and lack of linkage with essential hypertension

Essential hypertension, a clinically significant elevation in blood pressur e with no recognizable cause, is believed to be attributable to the collect ive effect of genetic predisposing factors in combination with specific env ironmental factors, such as diet and stress. Of the genetic causes, genes c oding for proteins involved in blood pressure regulation, such as the alpha - and beta-adrenergic receptors, are obvious candidates. The alpha(2)-adren ergic receptor plays a key role in the sympathetic nervous system by mediat ing the effects of epinephrine and norepinephrine. To evaluate the potentia l role between the alpha(2B)-receptor and essential hypertension, we scanne d the alpha(2B)-receptor gene for genetic variation in 108 affected sibling pairs. The screening revealed two major forms of the receptor. They differ by the presence of either 9 or 12 glutamic acid residues in the acidic dom ain of the third cytoplasmic loop of the protein. Investigation of the patt ern of this variation in hypertensive sibling pairs suggests that the alpha (2B) receptor locus does not contribute substantially to genetic susceptibi lity for essential hypertension. Am J Hypertens 1999;12:853-857 (C) 1999 Am erican Journal of Hypertension, Ltd.