AFRICAN AMERICANS : MEDICAL: HEART: BLOOD PRESSURE : MEDICAL: GENETICS: Researchers Uncover Genetic Variants Linked to Blood Pressure in African-Americans

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AFRICAN AMERICANS : MEDICAL: HEART: BLOOD PRESSURE : MEDICAL: GENETICS: Researchers Uncover Genetic Variants Linked to Blood Pressure in African-Americans

David P. Dillard


Researchers Uncover Genetic Variants Linked
to Blood Pressure in African-Americans

Date: Fri, 17 Jul 2009 09:12:52 -0400
From: "NIH OLIB (NIH/OD)" <[hidden email]>
To: [hidden email]


U.S. Department of Health and Human Services

National Human Genome Research Institute (NHGRI)

Embargoed for Release: Thursday, July 16, 2009, 8:01 p.m. EDT


Raymond MacDougall



[hidden email]


Findings May Point to New Avenues for Treatment, Prevention

A team led by researchers from the National Institutes of Health (NIH)
today reported the discovery of five genetic variants related to blood
pressure in African-Americans, findings that may provide new clues to
treating and preventing hypertension. The effort marks the first time that
a relatively new research approach, called a genome-wide association
study, has focused on blood pressure and hypertension in an
African-American population.

Hypertension, or chronic high blood pressure, underlies an array of
life-threatening conditions, including heart disease, stroke and kidney
disease. Diet, physical activity and obesity all contribute to risk of
hypertension, but researchers also think genetics plays an important role.

About one-third of U.S. adults suffer from hypertension. The burden is
considerably greater in the African-American community, in which the
condition affects 39 percent of men and 43 percent of women.

"This work underscores the value of using genomic tools to untangle the
complex genetic factors that influence the risk for hypertension and other
common diseases," said Eric Green, M.D., Ph.D., scientific director for
the National Human Genome Research Institute (NHGRI), part of NIH. "We
hope these findings eventually will translate into better ways of helping
the millions of African-Americans at risk for hypertension, as well as
improved treatment options for other populations."

In addition to NHGRI researchers, scientists from the Coriell Institute
for Medical Research in Camden, N.J.; Boston University; and Howard
University, in Washington, D.C., collaborated on the study, which was
published in the July 17 online issue of PLoS Genetics.

To produce their findings, researchers analyzed DNA samples from 1,017
participants in the Howard University Family Study, a multigenerational
study of families from the Washington, D.C., metropolitan area who
identified themselves as African-American. Half of the volunteers had
hypertension and half did not. To see if there were any genetic
differences between the two groups, researchers scanned the volunteers'
DNA, or genomes, analyzing more than 800,000 genetic markers called
single-nucleotide polymorphisms (SNPs).

The researchers found five genetic variants significantly more often in
people with hypertension than in those without the condition. The variants
were associated with high systolic blood pressure, but not with diastolic
blood pressure or combined systolic/diastolic blood pressure.

Blood pressure is measured in millimeters of mercury (mm Hg), and
expressed with two numbers; for example, 120/80 mm Hg. The first number
(systolic pressure) is the pressure when the heart beats while pumping
blood. The second number (diastolic pressure) is the pressure in large
arteries when the heart is at rest between beats.

"This is the first genome-wide association study for hypertension and
blood pressure solely focused on a population with majority African
ancestry," said the study's senior author, Charles Rotimi, Ph.D., NHGRI
senior investigator and director of the trans-NIH Center for Research on
Genomics and Global Health (CRGGH). "Although the effect of each
individual genetic variant was modest, our findings extend the scope of
what is known generally about the genetics of human hypertension."

In a genome-wide association study, researchers identify strategically
selected markers of genetic variation. If disease status differs for
individuals with certain genetic variants, this indicates that something
in that chromosomal neighborhood likely influences the disease. Variants
detected using this approach can accurately point to the region of the
genome involved, but may not themselves directly influence the trait.

In May, two major international studies used the genome-wide association
approach to identify 13 genetic variants associated with blood pressure
and hypertension in people with primarily European and South Asian
ancestry.  While each variant was associated with only a slight increase
in blood pressure, that work found that the more variants an individual
had, the greater his or her risk of hypertension. Two genes identified by
one of those studies were also associated with blood pressure in the new

In their pioneering study of African-Americans, Dr. Rotimi and his
colleagues found that all of the five genetic variants associated with
blood pressure were located in or near genes that code for proteins
thought to be biologically important in hypertension and blood pressure.
Previous research had implicated two of those genes in blood pressure
regulation, and additional analyses by Dr. Rotimi's group revealed that
all of the variants are likely involved in biological pathways and
networks related to blood pressure and hypertension.

An existing class of anti-hypertension drugs, called calcium channel
blockers, already targets one of the genes, CACNA1H. However, the
additional genes may point to new avenues for treatment and prevention.

To follow up and expand upon their findings in African-Americans, the
researchers scanned DNA from 980 West Africans with and without
hypertension. The work confirmed that some of the genetic variants
detected in African-Americans were also associated with blood pressure in
West Africans. "The Western African population is of particular
significance since it is the ancestral population of many
African-Americans," said lead author Adebowale Adeyemo, M.D., CRGGH staff

This study was supported by the NHGRI, CRGGH, and the National Institute
of General Medical Sciences, all part of NIH; and by a W.W. Smith
Foundation grant to the Coriell Institute. The Howard University General
Clinical Research Center carried out the enrollment of study participants.

For more information about hypertension, visit


To learn more about the genome-wide association approach, visit


NHGRI is one of the 27 institutes and centers at the NIH, an agency of the
Department of Health and Human Services. The NHGRI Division of Intramural
Research develops and implements technology to understand, diagnose and
treat genomic and genetic diseases. Additional information about NHGRI can
be found at its Web site,


The National Institutes of Health (NIH) -- The Nation's Medical Research
Agency -- includes 27 Institutes and Centers and is a component of the
U.S. Department of Health and Human Services. It is the primary federal
agency for conducting and supporting basic, clinical and translational
medical research, and it investigates the causes, treatments, and cures
for both common and rare diseases. For more information about NIH and its
programs, visit



This NIH News Release is available online at:

Bushell, R. & Sheldon, P. (eds),
Wellness and Tourism: Mind, Body, Spirit,
Place, New York: Cognizant Communication Books.
Wellness Tourism: Bibliographic and Webliographic Essay
David P. Dillard


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