The researchers compared people who drank one to two sweetened soft drinks, fruit drinks, iced tea, energy drinks, or vitamin water every day with people who had one or no sweetened beverage over the course of a month to see which group was more likely to develop type 2 diabetes or metabolic syndrome. A precursor to diabetes, this syndrome includes high blood sugar, high blood pressure, high abdominal body fat, and high levels of “bad’’ cholesterol.

By a GenomeWeb staff reporter

NEW YORK (GenomeWeb News) – Chinese researchers reported in today’s issue of the Journal of the American Medical Association that they have uncovered genetic variants linked to serious kidney complications in Chinese individuals with type 2 diabetes.

The researchers followed nearly 1,200 Chinese individuals with type 2 diabetes over several years, using genotyping to look for associations between a kidney complication called end-stage renal disease and 18 common SNPs in and around PRKCB1, a protein kinase C-beta signaling protein gene. Indeed, the team found a quartet of SNPs in this region that were associated with end-stage renal disease in Chinese patients with type 2 diabetes.

“Our consistent results … suggest that genetic variation in the PRKCB1 gene is an important determinant for the risk of developing DKD in Chinese patients with type 2 diabetes,” corresponding author Ronald Ma, a medicine and therapeutics researcher at the Chinese University of Hong Kong, and his co-authors wrote.

Their models suggest the alleles might provides clues about which diabetes patients are at risk of kidney complications, with individuals carrying more of the risk alleles apparently at higher risk than those who have none or just one.

Some 94 million or more adults in China have type 2 diabetes, the researchers noted. And Chinese diabetics seem to be at higher risk of diabetes-related kidney problems and kidney failure than those from other populations, with past research finding that roughly one to three percent of Chinese diabetics develop diabetes related kidney problems.

Because diabetic kidney disease seems to have a strong — but largely uncharacterized — genetic component, Ma and his co-workers decided to look for common genetic variants linked to end-stage renal disease in Chinese diabetics, focusing on 18 SNPs in and around PRKCB1 — a gene previously linked to some diabetes complications and kidney-related processes in human and animal studies.

For the initial phase of the study, the team assessed the PRKCB1 SNPs in genomic DNA from 1,172 unrelated individuals with type 2 diabetes who had been recruited to the Hong Kong Diabetes Registry between 1995 and 1998. The samples were genotyped using the Sequenom MassArray platform at McGill University and the Genome Quebec Innovation Centre.

Of the 1,172 individuals tested, 7.7 percent went on to develop end-stage renal disease over a mean follow-up time of 7.9 years.

When they looked for variants linked to such kidney problems using genotype data, combined with information on Chinese population structure from HapMap, the researchers found that four of the SNPs were significantly associated with end-stage renal disease.

And the risk alleles seemed to have a cumulative influence on end-stage kidney disease risk: the researchers estimated that individuals with four risk alleles are about six times more likely to develop the kidney condition than those with none of the risk alleles or with a single risk allele.

The team subsequently verified the associations between end-stage renal disease and PRKCB1 SNPS in another 1,049 individuals who were recruited after 1998 and had been diagnosed with type 2 diabetes before the age of 45 years old.

Of these participants, 151 developed chronic kidney disease, though researchers noted that follow-up time was shorter than it had been in the initial cohort. Again, the presence of PRKCB1 variants seemed to up the risk of kidney troubles in an additive way.

More research is needed to untangle the functional consequence of the PRKCB1 variants, though the team’s initial bioinformatics search hints that the SNPs identified in the current study might impact transcription of PRKCB1.

Based on its findings, combined with previously reported results from other groups, the team speculated that “the risk association of renal disease with PRKCB1 may be mediated by interacting pathways, including but not limited to hyperglycemia, and increased oxidative stress causing tubular damage and interstitial fibrosis.”

Moreover, the researchers noted that the results in the Chinese population may also provide insights into the appropriate use of ruboxistaurin, a protein kinase C-beta inhibiting compound that is being tested for the treatment of other diabetes-related complications.

“Given the phenotypic and genetic heterogeneity of complex diseases such as [diabetic kidney disease], it would be of interest to examine the interaction between PRKCB1 genotype and clinical response to ruboxistaurin,” Ma and his co-authors wrote.

Related articles by Zemanta

• Genetic variations linked with development of ESRD in Chinese patients with diabetes (eurekalert.org)
• Gene Variants Put Diabetics at Risk of Kidney Disease (nlm.nih.gov)

Posted on: Monday, 13 September 2010, 00:59 CDT

REYKJAVIK, Iceland, September 13, 2010 /PRNewswire-FirstCall/ –

- SNP on Chromosome 7 is Rare Among Chinese but Confers Five-Fold
Increase in Risk; Underscores Importance of Analyzing Risk Factors Across
Continental Ancestries

Scientists at deCODE genetics and academic colleagues from Iceland,
China, Sweden, the UK and Australia today report the discovery of the most
important single-letter variation (SNP) in the sequence of the human genome
yet associated with risk of primary open-angle glaucoma. This is the most
common form of glaucoma and a major cause of blindness worldwide.

The SNP on chromosome 7q31 is common among Europeans, with approximately
6% of people of European ancestry carrying two copies of the at-risk version,
putting them at roughly 60% greater risk of developing the disease than those
who carry none. But among Chinese, the impact of the SNP is markedy
different. In study groups from Hong Kong and Shantou, the at-risk version of
the SNP is shown to be carried by less than 1% the population, but each copy
carried confers a more than five-fold increase in risk. The SNP is near the
genes encoding caveolin 1 and 2, membrane proteins that are expressed in the
meshwork that drains fluid from the eye, a process that if disturbed can
increase pressure on the optic nerve and lead to glaucoma.

“The key to reducing the personal and public health impact of glaucoma is
early diagnosis and treatment to slow the loss of sight. Discoveries such as
today’s, which follows on our previous landmark findings in exfoliation
glaucoma, are important because we can fold them directly into tests to
target screening and to detect and treat more disease earlier. Moreover,
among Chinese this latest SNP alone can define a small fraction of the
population that should be very carefully screened. This underscores the value
of being able to systematically analyze the impact of genetic risk factors
across continental ancestries. Not only are these markers medically useful,
they also tell us a bit about evolution and the spread of humanity across the
globe,” said Kari Stefansson, deCODE’s Executive Chairman and President of
Research and senior author of the study.

The authors would like to thank the more than 40,000 people who
participated in this study, both glaucoma patients and control subjects. The
paper, “Common variants near CAV1 and CAV2 are associated with primary
open-angle glaucoma,” is published online in Nature Genetics at
http://www.nature.com/ng and will appear in an upcoming print edition of the
journal.

Primary open-angle glaucoma is a disease in which the optic nerve becomes
damaged, leading to a progressive loss of sight. It affects tens of millions
of people worldwide, mostly those over the age of 50. Incidence increases
with age and varies between populations. Other known risk factors include
high blood pressure and diabetes. Current treatments include eye drops that
reduce pressure on the optic nerve, as well as surgery.

About deCODE

Headquartered in Reykjavik, Iceland, deCODE genetics is a global leader
in analyzing and understanding the human genome. Using its unique expertise
and population resources, deCODE has discovered key genetic risk factors for
dozens of common diseases ranging from cardiovascular disease to cancer.
deCODE employs its capabilities to develop DNA-based tests and personal
genome scans to better understand individual risk and empower prevention. It
also licenses its tests, intellectual property and analytical tools to
partners, and provides comprehensive genotyping, sequencing and data analysis
services to companies and research institutions around the globe. Through its
CLIA- and CAP-certified laboratory deCODE offers DNA-based tests for gauging
risk and empowering prevention of common diseases, including deCODE
Glaucoma(TM); deCODE T2(TM) for type 2 diabetes; deCODE AF(TM) for atrial
fibrillation and stroke; deCODE MI(TM) for heart attack; deCODE
ProstateCancer(TM); and deCODE BreastCancer, for the common forms of breast
cancer. Through its pioneering personal genome analysis service deCODEme(TM),
deCODE enables individuals to better understand their risk of dozens of
common diseases and to learn about their ancestry and other traits. Visit us
on the web at http://www.decode.com; at http://www.decodediagnostics.com; at
http://www.decodeme.com; and on our blog at http://www.decodeyou.com.

Contacts:

Edward Farmer
+354-863-1923
edward.farmer@decode.is

Gisli Arnason
+354-570-1900
info@decode.is

SOURCE DeCODE Genetics Inc

Source: PR Newswire

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