University of Chicago genetics team identifies Asthma Susceptibility Gene PYH1N1 Unique to African Americans, Afro-Caribbeans....

University of Chicago genetics team identifies Asthma Susceptibility Gene PYH1N1 Unique to African Americans, Afro-Caribbeans; Two Other ‘Asthma’ Genes CRCT1 and GSDMB Impact European-Americans, African Americans and Latinos

As researchers and others in the scientific and medical community have long suspected, asthma is caused in part by genetic factors, explaining asthma’s high prevalence in minority communities.

A team of geneticists identified an asthma susceptibility gene called PYH1N1 that occurs only in individuals of African descent. The study, published in the July 31, 2011 online issue of Nature Genetics, was led by Dr. Carole Ober, co-chair of the EVE Consortium, and who is Blum-Riese Professor of human genetics and obstetrics/gynecology at the University of Chicago. Dr. Dan Nicolae, associate professor of medicine, statistics, and human genetics at University of Chicago was also a senior author of the study along with other team scientists and researchers.

PYHIN1 "may be the first asthma susceptibility gene identified that is specific to populations of African descent," Ober, Nicolae and other researchers wrote in the Nature Genetics article.

Using data assembled from nine previous genome-wide association studies, collectively known as the EVE Consortium, researchers analyzed a total of more than 2 million single nucleotide polymorphisms (SNPs) in 3,246 asthma patients, 3,385 non-asthmatic controls, 1,702 patient-parent groupings, 355 family-based cases, and 468 family-based controls.

The study found that this gene is not a rare variant, anywhere from 26% to 29% of individuals of African descent carry at least one copy, the researchers wrote.
The populations in these groups mentioned above were broadly categorized as African-American and Afro-Caribbean individuals, Latin Americans and European Americans.
Two other genes that increased the risk of asthma in Whites, Latinos and African-Americans and was also identified. These two genes are known as CRCT1 and GSDMB.

Naturally, there are numerous reasons why an individual may develop asthma and simply because an individual (of any ethnic background) does not have this gene does not automatically protect them from ever developing asthma.
The researchers noted while the associations found in this research are key they do not necessarily imply causality. In other words asthma’s genetic component is only partially a factor and/or potentially influenced by other genes, environmental factors, susceptibility factors and perhaps other reasons as well.
Having any of these ‘asthma’ genes does not necessarily mean a 100% guarantee of asthma in one’s lifetime, but makes it much more likely. Additional questions could include why do some individuals develop asthma as children, while others as adults? Why do asthma symptoms seemingly recede in some children as they grow? Is there a genetic factor in this process or is it a environmental and/or a benefit of older and stronger lungs and general constitutions?
While the study did not explicitly cover this topic since such widespread mass market asthma genetics tests in doctor’s offices may not be common for years, perhaps even decades, I was wondering when and if individuals might be able to take a test and know if they have this PYH1N1 gene. Will they be able to give you a useful approximation if you will develop asthma? Would such a test or genetic screening really benefit us? And thinking even further down the line about pre-natal genetic testing: imagine the scenario, of a doctor telling a mother-to-be, Congratulations, your baby is doing well, but may be at a higher risk of developing asthma since we have identified the PYH1N1 gene.

Torgerson D, et al "Meta-analysis of genome-wide association studies of asthma in ethnically diverse North American populations" Nature Genetics 2011; DOI: 10.1038/ng.888.