July 3, 2013
Genetic Associations Found In Pollen, Dust And Cat Allergies
April Flowers for redOrbit.com - Your Universe Online
Sixteen new genetic associations, including pollen, dust-mite and cat allergies, have been identified by the largest genome-wide association study ever conducted on common allergies.23andMe, the leading personal genetics company, and the Avon Longitudinal Study of Parents and Children (ALSPAC) collaborated on the study, which examined data for more than 53,000 individuals.
The study, published in Nature Genetics, also identified eight genetic variations for allergies that have previously been associated with asthma. A series of key pathways in the biological basis of common allergies are highlighted by the genes implicated in the study.
In the industrialized world, allergies and allergic asthma are among the most common diseases. A 2005 survey in the US revealed more than half of the population tested positive for sensitivity to at least one of the ten most common allergens. This shows a considerable increase compared to the results of the same survey performed ten years earlier.
"We've seen some substantial increases in prevalence of allergies and asthma," said David Hinds, PhD, 23andMe principal scientist. "Although environmental factors certainly play a role, our study reinforces the genetic link between common allergens and a person's susceptibility to experiencing an allergic reaction. Additionally, current estimates of the heritability of allergies are high, which suggests that understanding the genetic factors underlying allergic conditions may be key to understanding who might be most likely to suffer from allergies and how the condition might best be treated."
Three common self-reported allergy phenotypes -- pollen, dust-mite and cat allergies -- were selected for the study. Comparable data was available for these phenotypes both in the 23andMe research community and in a cohort from ALSPAC. The data from both were included in a genome-wide association meta-analysis.
"Allergy is an important component of many diseases, including asthma, eczema and hay fever, which together account for a huge burden on patients and the health services." said Professor John Henderson of ALSPAC. "This is a very exciting time for allergy research. Genetic discoveries have identified specific pathways of allergy development that are not shared with allergic diseases like asthma. Understanding these pathways could lead to eventual development of drugs that cure or prevent allergy rather than just suppressing its symptoms."
"One of the key features of this work is the demonstration that with a suitably sized study, the analysis of medically relevant questionnaire data alongside genetic variation has the potential to yield important information concerning the underlying biology of a complex outcome," said Dr. Nic Timpson of ALSPAC. "Indeed, through this collaborative interaction with colleagues from EAGLE where specific tests of allergic sensitization were available, we were able to independently replicate many of the findings made here."
EAGLE, the Early Genetics and Lifecourse Epidemiology research cohort, conducted a companion study, also published in Nature Genetics. The EAGLE researchers used clinically defined data instead of self-reported data, which provided the opportunity to compare results of self-reported data to study results based on clinically defined data. The results of the two studies were very consistent in general, and highlighted many of the same genes and pathways.
"This coordinated approach to research significantly accelerates the replication and validation processes associated with solidifying new genetic discoveries," said Hinds.
"Through this collaborative effort, we have identified several genes that are responsible for a considerable proportion of allergy in the population," said Klaus Bonnelykke, MD, PhD and principal scientist from EAGLE. "This is an important step in allergy research."