Identification of a polymorphic glutamic acid stretch in the α2B-adrenergic receptor and lack of linkage with essential hypertension

Essential hypertension, a clinically significant elevation in blood pressure with no recognizable cause, is believed to be attributable to the collective effect of genetic predisposing factors in combination with specific environmental factors, such as diet and stress. Of the genetic causes, genes coding for proteins involved in blood pressure regulation, such as the alpha- and beta-adrenergic receptors, are obvious candidates. The alpha(2)-adrenergic receptor plays a key role in the sympathetic nervous system by mediating the effects of epinephrine and norepinephrine. To evaluate the potential role between the alpha(2B)-receptor and essential hypertension, we scanned 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 domain of the third cytoplasmic loop of the protein. Investigation of the pattern of this variation in hypertensive sibling pairs suggests that the alpha(2B) receptor locus does not contribute substantially to genetic susceptibility for essential hypertension. Am J Hypertens 1999;12:853-857 (C) 1999 American Journal of Hypertension, Ltd.