Drug News Genetic testing no better predictor for diabetes risk
By Sue Mueller
Nov 22, 2008 - 5:56:19 AM
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Want to know your diabetes risk? No need to visit a genetic testing laboratory! A new study published in the Nov 20 2008 issue of the New
England Journal of Medicine suggests that use of a set of 16 genetic variants
is not significantly better than use of common clinical risk factors when it comes to predicting the risk of type 2 diabetes.
The study was conducted by researchers from Lund
University, Malmö, Sweden, the University of Helsinki and the Program in
Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge,
MA, and Massachusetts General Hospital, Boston.
The notion that type 2 diabetes mellitus results from an
interaction between environmental and genetic factors led the researchers to
believe that genetic variants could be better predict the risk of type 2
diabetes than clinical factors.
In the study, Lyssenko V and colleagues conducted DNA genetic testing for 16 genes and examined clinical factors in 16,000 Swedish and
2770 Finnish subjects.
Type 2 diabetes
were diagnosed in 2201 or 11.7 percent of the subjects during the average 23.5-year
follow-up.
Conventional predictors of diabetes include family
history of diabetes, high body mass index, elevated liver-enzyme levels,
smoking status and reduced measures of insulin secretion and action.
The genetic variants studied include those in 11 genes
(TCF7L2, PPARG, FTO, KCNJ11, NOTCH2, WFS1, CDKAL1, IGF2BP2, SLC30A8, JAZF1, and
HHEX), which were significantly associated with the risk of type 2 diabetes
independently of clinical risk factors and 8 of these genes which were
associated with impaired beta-cell function.
The researchers found that adding genetic information to
clinical factors slightly improved the prediction of future diabetes. The
significance of genetic variants in the predictability increased with the
increasing duration of follow-up.
They concluded that "As compared with clinical risk
factors alone, common genetic variants associated with the risk of diabetes had
a small effect on the ability to predict the future development of type 2
diabetes. The value of genetic factors increased with an increasing duration of
follow-up."
But overall, genetics testing employed in this study does not seem to be superior to the traditional assessment on the diabetes risk based on clinical parameters.
Source:
New England Journal of Medicine. 2008 Nov
20;359(21):2220-2232.
Clinical Risk Factors, DNA Variants, and the Development
of Type 2 Diabetes.
Lyssenko V, Jonsson A, Almgren P, Pulizzi N, Isomaa B,
Tuomi T, Berglund G, Altshuler D, Nilsson P, Groop L.
From the Department of Clinical Sciences, Lund
University, Malmö, Sweden (V.L., A.J., P.A., G.B., P.N., L.G.); the University
of Pisa, Pisa, Italy (N.P.); the Folkhalsan Research Center (B.I., T.T.) and
Helsinki University Central Hospital and the University of Helsinki (T.T.,
L.G.) - all in Helsinki, Finland; and the Program in Medical and Population
Genetics, Broad Institute of Harvard and MIT, Cambridge, MA, and Massachusetts
General Hospital, Boston (D.A.).