Gene Causing Childhood Asthma Differs Among US, Afro-Americans Kids

by VR Sreeraman on Sep 16 2008 6:37 PM

A gene variant responsible for increasing the risk of childhood asthma in European children acts the same way in white American kids, but not in African American children, says a new study.

Asthma is the most common chronic illness among children in the developed world, and is quite complex in nature where a variety of genes are thought to interact with each other and with environmental influences to produce its effects.

An additional knowledge of gene associations related with asthma will pave the way for new treatments and to customizing treatments to each patient's genetic profile.

Researchers from The Children's Hospital of Philadelphia found that variants in the ORMDL3 gene were associated with childhood-onset asthma among U.S. patients of European ancestry.

In 2007, a European study had identified that the ORMDL3 gene, located on chromosome 17, contributes to childhood asthma among British and German children.

"We replicated the European findings among American children, and showed that the gene plays a role in asthma of any severity level. The previous group had detected the association of ORMDL3 with asthma by examining families having two or three members with severe disease," said study leader and pediatric pulmonologist Hakon Hakonarson, M.D., Ph.D., director of the Center for Applied Genomics at Children's Hospital.

He added: "Through the testing of additional markers, our data suggest that other genes outside the region occupied by ORMDL3 might have important roles in raising susceptibility to asthma."

Now, his group is planning additional studies to further refine this and other regions.

After collecting data on patients from the Children's Hospital network, the researchers analyzed DNA from 807 white children with asthma, compared to 2,583 white children without the disease.

They also analysed another cohort consisted of African American children, of whom 1,456 had asthma and 1,973 were healthy controls. The researchers used highly automated gene-scanning equipment at Children's Hospital's Center for Applied Genomics, the largest pediatric genotyping program in the world.

"Because asthma is a very heterogeneous disease, the genes involved in childhood-onset asthma may be very different from those involved in asthma that first appears in adults," said Hakonarson.

He added: "Furthermore, the biological mechanisms by which genetic variants contribute to asthma are not well understood. However, we will continue our investigations, to shed light on how we might use genetic knowledge to develop more effective treatments for this common disease. These treatments will be a form of personalized medicine, better tailored to the genetic makeup of the individual patient."

The study appeared as a brief online report in the Journal of Allergy and Clinical Immunology.