- In Children's DNA, a Hint of a Mutation's Ancestral African Origin -
PHILADELPHIA, March 12 /PRNewswire-USNewswire/ -- Genomics researchers,
seeking to replicate another group's discovery of an important gene
associated with obesity, have further refined the signal to a particular
variant in DNA that may be more helpful in identifying this gene's role in
obesity in various human populations worldwide. The finding suggests that
the gene variant, identified in DNA from African American children, may be
a tag of an ancient mutation that first arose in Africa, where humans
originated.
The research team, led by Struan Grant, Ph.D., and Hakon Hakonarson,
M.D., Ph.D., both of the Center for Applied Genomics of The Children's
Hospital of Philadelphia, was studying the FTO gene, identified by a
British group in 2007 as raising the risk of adult and childhood obesity.
Although environmental influences are certainly important, family studies
have indicated that obesity has a genetic component as well.
The research team, from Children's Hospital and the University of
Pennsylvania School of Medicine, reported its findings in the March 12
issue of the journal Public Library of Science ONE.
The 2007 British group had originally found the FTO gene variant among
obese Caucasians. Using samples from Caucasian and African American
children, who were either obese or not, the Children's Hospital group used
a genetic screening technique to replicate the previous finding. They found
the same gene variant among Caucasian children, but not among the African
American children.
Instead, a second variant, found in both Caucasians and African
Americans, was the only marker significantly linked to obesity among the
African American children. Both variants were changes to a single chemical
base along the DNA strand, which geneticists call single nucleotide
polymorphisms, or SNPs.
For genomics researchers, said Grant, the findings mean that if other
investigators look only for the first SNP in subjects with African
ancestry, they would find no association with obesity. The second SNP may
have deep roots in evolutionary history. Scientists have multiple lines of
evidence indicating that humans originated in Africa, and this SNP may be
related to an original mutation in the distant past that initiated a human
predisposition to obesity.
The fact that mutations in the FTO gene carry a comparable risk of
obesity in both children and adults, said Grant, suggests that the gene may
be primarily associated with obesity that begins in childhood. Future
medical treatments may benefit patients by targeting the FTO gene pathway,
added Grant, although such treatments await a better understanding of the
underlying biology of obesity.
The study team will continue to seek out other possible gene variants
within the FTO gene, plus other genes that may be involved in obesity. The
Center for Applied Genomics at Children's Hospital is currently the largest
pediatric genotyping program in the world.
Dr. Grant's and Dr. Hakonarson's co-authors were Robert I. Berkowitz,
M.D., Mingyao Li, Ph.D., Jonathan P. Bradfield, Cecilia E. Kim, Kiran
Annaiah, Erin Santa, Joseph T. Glessner, Tracy Casalunovo, Edward C.
Frackelton, F. George Otieno, Julie L. Shaner, Ryan M. Smith, Marcin
Imielinski, M.D., Ph.D., Andrew W. Eckhert, and Rosetta M. Chiavacci.
About The Children's Hospital of Philadelphia: The Children's Hospital
of Philadelphia was founded in 1855 as the nation's first pediatric
hospital. Through its long-standing commitment to providing exceptional
patient care, training new generations of pediatric healthcare
professionals and pioneering major research initiatives, Children's
Hospital has fostered many discoveries that have benefited children
worldwide. Its pediatric research program is among the largest in the
country, ranking third in National Institutes of Health funding. In
addition, its unique family-centered care and public service programs have
brought the 430-bed hospital recognition as a leading advocate for children
and adolescents. For more information, visit http://www.chop.edu.
Contact: John Ascenzi
Phone: (267) 426-6055
Ascenzi@email.chop.edu
SOURCE The Children's Hospital of Philadelphia
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Related links:
http://www.chop.edu
CONTACT:
John Ascenzi of The Children's Hospital of
Philadelphia, +1-267-426-6055, Ascenzi@email.chop.edu
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