Familial and Genomic Analyses of Postural Changes in Systolic and Diastolic Blood Pressure

• Published in: Hypertension (Dallas, Tex. 1979) Vol. 43; no. 3; pp. 586 - 591
• Main Authors: Harrap, Stephen B, Cui, Jisheng S, Wong, Zilla Y. H, Hopper, John L
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01.03.2004; Hagerstown, MD Lippincott
• Subjects: Adult; Aged; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood Pressure - genetics; Cardiology. Vascular system; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Diastole - genetics; Female; Fundamental and applied biological sciences. Psychology; Genetic Linkage; Genome, Human; Hemodynamics. Rheology; Humans; Male; Medical sciences; Middle Aged; Nuclear Family; Phenotype; Posture; Quantitative Trait Loci; Systole - genetics; Vertebrates: cardiovascular system; Human; Cartography; Systolic pressure; blood pressure; Nervous system diseases; Diastolic pressure; Cardiovascular disease; Chromosome; Sibling; Posture; population; Postural hypotension; Phenotype; Baroreflex; Diseases of the autonomic nervous system; Genetic linkage; Genome
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/01.HYP.0000118044.84189.44

ABSTRACT—The physiological adaptation to the erect posture involves integrated neural and cardiovascular responses that might be determined by genetic factors. We examined the familial- and individual-specific components of variance for postural changes in systolic and diastolic blood pressure in 767 volunteer nuclear adult families from the Victorian Family Heart Study. In 274 adult sibling pairs, we made a genome-wide scan using 400 markers for quantitative trait loci linked with the postural changes in systolic and diastolic pressures. Overall, systolic pressure did not change on standing, but there was considerable variation in this phenotype (SD=8.1 mm Hg). Familial analyses revealed that 25% of the variance of change in systolic pressure was attributable to genetic factors. In contrast, diastolic pressure increased by 6.3 mm Hg (SD=7.0 mm Hg) on standing and there was no evidence of contributory genetic factors. Multipoint quantitative genome linkage mapping suggested evidence (Z =3.2) of linkage of the postural change in systolic pressure to chromosome 12 but found no genome-wide evidence of linkage for the change in diastolic pressure. These findings suggest that genetic factors determine whether systolic pressure decreases or increases when one stands, possibly as the result of unidentified alleles on chromosome 12. The genetics of postural changes in systolic blood pressure might reflect the general buffering function of the baroreflex; thereby, the predisposition to sudden decreases or increases in systolic pressure might cause postural hypotension or vessel wall disruption, respectively.