Alpha- and beta-adrenergic receptor polymorphisms in hypertensive and normotensive offspring.
BACKGROUND
The offspring of hypertensive families are characterized by higher arterial blood pressure values and a depressed autonomic control of heart rate. The present study aimed to verify whether these differences are associated with a different genotype distribution of functionally relevant polymorphisms of the alpha- and beta-adrenergic receptor (AR) genes.


METHODS
We selected 109 age- and sex-matched young normotensive subjects with (FH+, n = 56) and without (FH-, n = 53) a family history of hypertension who underwent evaluation of arterial pressure; 24-h electrocardiogram monitoring to assess time-domain parameters of autonomic heart rate control [i.e. mean RR interval (NN), SD of RR intervals (SDNN) and mean square root of the differences of consecutive RR intervals (rMSSD)]; spectral baroreflex sensitivity measurement; and echo-Doppler to assess diastolic function and left ventricular mass. They were also characterized for the following polymorphisms by means of polymerase chain reaction-restriction fragment polymorphism analysis: Arg492Cys in the alpha1a-AR; Del301-303 in the alpha2b-AR; Ser49Gly and Arg389Gly in the beta1-AR; and the 5' leader cistron Arg19Cys, Arg16Gly and Gln27Glu in the beta2-AR.


RESULTS
FH+ individuals showed a higher systolic pressure, a lower SDNN and a greater isovolumic relaxation time compared to normotensive offspring. No differences were found between the two groups when genotype distribution of the studied polymorphisms was considered. Subjects carrying alpha1a-AR Cys492 allelic variant showed lower values of NN, SDNN and rMSSD, independent of age, gender and body mass index.


CONCLUSIONS
The functionally relevant polymorphisms of alpha2b-, beta1- and beta2-AR genes are not associated with a family history of essential hypertension. The Arg492Cys polymorphism of the alpha1a-AR gene, although not associated with a family history of hypertension, was strongly related to autonomic control of heart rate.
Iacoviello
Massimo
M
Institute of Cardiology, University of Bari, Bari, Italy. massimo.iacoviello@cardio.uniba.it
Forleo
Cinzia
C
Sorrentino
Sandro
S
Romito
Roberta
R
De Tommasi
Elisabetta
E
Lucarelli
Katya
K
Guida
Pietro
P
Pitzalis
Maria Vittoria
MV
D000328:Adult; D000704:Analysis of Variance; D017704:Baroreflex / Q000235:genetics; D001794:Blood Pressure / Q000235:genetics; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000235:genetics; D015150:Echocardiography, Doppler; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006339:Heart Rate / Q000235:genetics; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D006973:Hypertension / Q000235:genetics* / Q000503:physiopathology; D008297:Male; D011110:Polymorphism, Genetic; D011942:Receptors, Adrenergic, alpha / Q000235:genetics*; D011943:Receptors, Adrenergic, beta / Q000235:genetics*; D016277:Ventricular Function, Left / Q000235:genetics
D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta