Experts believe that the cause of asthma is multifactorial, which means that multiple factors are involved in the development of this condition. These factors are broadly classified as genetic and environmental factors.
Various risk factors are covered in detail in another article. Let’s review now some basic concepts of genetics and the genetics of asthma
The human body is made up of 50 trillion cells and each cell contains DNA or deoxyribonucleic acid. Nearly every cell in a person’s body has the same DNA. The DNA is organized into chromosomes and each human cell has 23 pairs of chromosomes or base pairs. Among the base pairs, one strand of DNA comes from the mother and one from the father.
The Human Genome Project (HGP) brought significant contributions to understanding how our genes work. One of their main goals was to map out or sequence the entire human genome. They found that the human genome contains about 21,000 genes. Next, the HGP sifted their research to better understand how various genetic components work together in health and disease.
The Genetics Of Asthma
Each gene contains a blueprint for creating proteins that instruct the cells to take certain actions.
Many genes are the same in all people. However, some genes undergo mutations. These mutations lead to certain characteristics and traits that make us unique.
The largest and most complex study on asthma genetics to date was conducted in 2010 and involved over 25,000 participants. This study identified special genes on chromosomes 2, 6, 9, 15, 17, and 22 associated with asthma. The ORMDL3 gene (chromosome 17), in particular, was linked with childhood-onset, whereas the HLA-DQ gene (chromosome 6) was related to later-onset asthma.
Unlike other conditions with genetic links, asthma is not caused by a single mutation in one gene. Based on the latest research, the combined action of several genes which interact one with one another and certain environmental factors cause asthma.
Asthma runs in families, and children who have a parent with asthma are at higher risk of having asthma. If both parents do not have asthma, the risk for the child to develop asthma is 5%. If one parent has asthma, the risk goes up to 25%. If both parents have asthma, the risk for the child to develop this condition is 50%.
Gene-environmental Interaction Is Essential
Genetic variations may be silent and become active when the environment is unhealthy- for example, exposure to air pollution, stress, smoking, respiratory infections, or allergens. The environmental factors explain in part why some people develop asthma during their adult years and not early in life.
Looking at genes alone is not enough and scientists tell us that the role of genes should be viewed in the context of a permissive environment. This field is known as epigenetics.
Epigenetics is the study of how the environment and your behaviors can affect the way your genes work.
Unlike genes that you can’t change, epigenetics is reversible. You can control and modify the way you eat, start working out, sleep better, manage stress, and avoid environmental pollutants. Epigenetics does not change the DNA sequence of a gene but changes how your body reads a DNA sequence and can turn” off” genes that may increase your risk of asthma or inflammation.
Lessons Learned From Genetics And Epigenetics
Lesson #1. Personalized medicine is the medicine of the future. Identifying the gene mutations associated with asthma was an important step in the research world. In the future, it is believed that treatments will be individualized according to genetics and lead to increased efficacy of the treatment. Doctors will be able to predict which patients could have the best response- for example, increased lung function when choosing one drug over another.
Lesson #2. Focus on things you can control. The world of epigenetics brings great news to everyone with asthma. You may have been born with some genetic susceptibility, but changing the environment and the behaviors can turn “off” the expression of those problematic gene mutations. Simply put, you need to eliminate unhealthy habits and replace them with healthy choices.
Exercise. Staying active is also important. Aim for 30 minutes of exercise most days of the week, and choose a workout that is asthma friendly.
Sleep is perhaps the most underestimated lifestyle change. Sleep deprivation has documented negative effects on genes. Most people need 7-8 hours of good night sleep. Although some people have a gene mutation that makes you naturally sleep less than six and a half hours each night without any apparent ill effects.
Stress management. Aim for 10 minutes of mindfulness meditation 1-2x/daily. Yoga and tai chi are great to relieve stress and keep you flexible too. Avoid spending too much time watching news on TV or social media.