A large, multi-ethnic genome-wide association study (GWAS) of asthma identified novel associations with potential relevance for asthma susceptibility in older adults of diverse racial backgrounds. The study, “Large-scale, multi-ethnic genome wide association study identifies novel loci contributing to asthma susceptibility in adults,” appears in the April issue of the Journal of Allergy and Clinical Immunology.
Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterize by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. These may occur a few times a day or a few times per week. Depending on the person, they may become worse at night or with exercise.
Combination of genetic
So asthma is thought to be cause by a combination of genetic and environmental factors. Environmental factors include exposure to air pollution and allergens. Other potential triggers include medications such as aspirin and beta blockers. Diagnosis is usually base on the pattern of symptoms, response to therapy over time, and spirometry.
Asthma affects over 300 million persons globally and susceptibility to asthma; which is influence by environmental and genetic risk factors. “Identifying the genetic variants associate with asthma through GWAS is crucial for determining the genetic basis of asthma” said co-first author Joanne Sordillo, ScD, MS, Research Scientist at the Harvard Pilgrim Health Care Institute.
It’s also necessary to understand how genetic heterogeneity underlying asthma risk; which may be influence by ethnic background, using large, multi-racial patient populations. Researchers conduct an asthma GWAS in the Kaiser Permanente Northern California Genetic Epidemiology Research in Adult Health and Aging (GERA) cohort, using a total of 68,623 asthma cases and non-asthmatic controls.
Potential mechanism for asthma
Hence study results find a novel potential mechanism for asthma susceptibility by the gene, IL1RL1. Study investigators believe this could be associate with asthma susceptibility through introduction of a new binding site for micro RNA, a small non-coding RNA molecule, that regulates expression of this locus.
So the study also replicate 16 novel associations with asthma susceptibility in the non-Hispanic white populations; so all of which were annotate to either HLA-DQA1, a major histocompatibility complex gene, or IL18R1/IL1RL1. Study results show no overlap in genome-wide asthma associations across the four ethnic groups; so suggesting that unique biological pathways may contribute to asthma susceptibility within older adults of different ethnicities.
Hence this study contributes novel and unique associations with asthma; hence within four major human ethnic groups and represents one of the largest GWAS of asthma conduct to date” said senior author Ann Chen Wu, MD, MPH. Associate Professor of Population Medicine at the Harvard Pilgrim Health Care Institute and Harvard Medical School.