Family History Of Asthma
Blame Mom or Dad or both for your asthma. Your inherited genetic makeup predisposes you to having asthma. In fact, it’s thought that three-fifths of all asthma cases are hereditary. According to a CDC report, if a person has a parent with asthma, they are three to six times more likely to develop asthma than someone who does not have a parent with asthma.
Genes Influencing The Inflammatory Pathways
It was around late 1980’s and early 1990s, when human chromosomal regions were first found to be linked with allergy or asthma . Since then various mediators of inflammation have been identified using approaches mentioned above . Several genome-wide screens have found linkage to chromosomal regions, such as, 5q23-31, 5p15, 6p21.3-23, 11p13, 11p15, 12q14-24.2, 13q21.3, 14q11.2-13, 17p11.1-q11.2, 19q13, 21q21 etc. . The most consistently replicated among them are 5q23-31, 5p15 and 12q14-24.2 containing genes like IL-3, IL-4, IL-5, IL-9, IL-12b, IL-13, IFN, iNOS, FCRI etc. . Most of these influence the T cell development/polarization towards Th1 or Th2 besides modulating other features like recruitment of eosinophils, mast cells, neutrophils etc. to the site of inflammation . These genes have also been validated using candidate gene approaches in different studies and a number of functional polymorphisms have been identified. It was found that the polymorphisms in the intronic region of IFN gene may be critical for IFN gene regulation and atopic asthma . Similarly inducible nitric oxide synthase or iNOS which is expressed predominantly by immune cells and epithelial cells harbor a number of promoter and intronic polymorphic repeats that could be regulating its expression and asthma related traits . Importantly, we had identified an intron 4 repeat to be associated with asthma severity .
Overlap Among Asthma And Allergic Diseases
Given the firm links in the pathogenesis of asthma and other allergic diseases , a few studies used this rationale to explore the overlapping genetic architecture among these diseases , including two large-scale GWAS published between 2016 and 2018 .
Table 4. Novel loci of asthma and allergic diseases revealed by meta-analyses published between 2016 and 2018.
Besides these findings, 29 of the genes identified by Ferreira et al. encode for proteins that are drug targets for several diseases, including allergic and auto-immune diseases. Interestingly, the protective effect of these genes was found to be correlated with the effect of drugs targeting them, attenuating allergy symptoms. These findings suggest that these could be effective targets to treat allergic diseases or asthma and thus, the proteins encoded by these should be prioritized for pre-clinical evaluation .
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What Some Causes Asthma
Science has not yet concluded the exact reasons for Asthma, but some have found exercising as a trigger to asthmatic symptoms. That said, there are some more identified triggers of asthmatic symptoms. These can vary from person to person:
- respiratory infections,
- coughing
What Are Some Treatments For Asthma?Asthma treatments help a patient manage the symptoms and prevent asthma attacks. Your doctor will recommend a combination of treatments.
- long-term asthma control medications
- steroids to reduce swelling
- fast-acting bronchodilators
Your doctor will most likely recommend that you implement some lifestyle changes to help control Asthma. Some changes could be:regular cleaning of your home
- identifying and avoiding triggers
- covering the mouth and nose in cold weather
- managing stress and strong emotions
If you feel youre having asthma symptoms and would like to consult a doctor, Book your appointment now at Internal Medicine Diagnostic Center. Call to schedule an appointment.
Is Asthma A Genetic Disorder
Asthma is one of the worst chronic diseases that haunt kids and adults alike. It is one of those diseases that can be controlled but is very hard to cure completely. There have been many speculations about whether or not Asthma is a genetic disorder. Let us seek a scientific explanation to this see if asthma must now be counted among hereditary diseases that couples need to be aware of before conceiving.
The Asthmatic Gene:
Allergic Asthma: Are Allergies Inherited Too?
Most doctors will tell you that allergic bronchitis is not genetic in nature. However, atopy is a hereditary disease. Atopy is basically a tendency to develop allergies or immunological reactions to certain allergens . In case of asthmatics, allergies are often respiratory ones. That is, instead of developing rashes or itchy feeling, you develop spasms. This happens because inner linings of your respiratory organs like nose, throat and lungs swell up when they come in contact with the particular allergens.
Some families have a tendency to have allergies that are common like allergy to peanuts, dust and pollen.
What Are The Odds?
Just a genetic predisposition to asthma will not make you prone to asthma attacks. Environmental factors play an equally important role in fostering asthma attacks. Suppose you have genetic asthmatic tendencies but you live on a hill station and breathe in pure air. Your chances of developing a chronic respiratory disorder are very less.
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Asthma Is A Genetic Disease
Hey guys I am having Asthma that is actually threatening my life…I am really depressed to think whether my child would genetically get that disease or not? Is that disease can be Genetically Transmitted or not?
How can I escape from Asthma Please let me know
Asthma is not a disease.
Asthma is a medical condition that cannot be transmitted from one person to another. It is caused by environmental degradation otherwise known as air pollution.
Grownup70, I think what she means is whether asthma is hereditary. Not pass it on in the way you would pass on a cold. You appear to be quite misguided about the causes and treatment of asthma, it’s not all caused by air pollution. If may be worth checking facts before misinforming other members with wrong information.
In answer to your question, there is evidence that asthma can be genetic and having one or two parents with asthma does increase the chances of passing it on, but there is no guarantee that it will be or that it will be severe. I wouldn’t let it deter you from living a fulfilled life, and if children are part of this, go for it!!
Hello Kummari,
I am so sorry you are so worried so I hope I can help.
I have just retired as a nurse specialist for children’s with respiratory disease after 12 years & now work as a children’s nurse.
Asthma is a conditions that is controllable & variable, it is also NOT heredity but it is a conditions that if mother and father have:-
asthma
eczema
hay fever
Hope that helps
Missing Heritability In Asthma And Allergic Diseases
It is possible that estimates of heritability for many complex phenotypes are inflated. This is particularly true for estimates based on twin studies because monozygotic twins not only share more of their genes compared to dizygotic twins , but they also share a more âidenticalâ environment than do dizygotic twins. In addition, the heritability of any particular trait may vary significantly in different environments and for different phenotypic subgroups , all of which are pooled in the large samples required for GWAS studies. As a result, the heritability for the trait under investigation may in fact be much smaller in the samples included in GWAS due to environmental and phenotypic heterogeneity.
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Hyperproliferation Of Airway Smooth Muscle Mass
Hyperproliferation of airway smooth muscle mass is a common event in asthma and has been suggested to be implicated in its pathophysiology. Hyperplasia and hypertrophy of the ASM in the bronchial airways of asthmatics can be observed by three-dimensional morphometric studies . Airways smooth muscle layer is estimated to be increased by 2555% in nonfatal asthma and up to 50200% in fatal asthma . Meanwhile, in response to some growth factors like TGF-, vascular endothelial growth factor , and connective tissue growth factor , ASM cells actively participate in the remodeling process through the process of ECM synthesis . ASM cells also express cellular adhesion molecules , receptors for cytokines , Toll-like receptors, and chemokines presenting multiple mechanisms for the inflammatory and remodeling process . Additionally, one characteristic event of the airway remodeling is the ASM cells migration toward the epithelium . Since ASM cells are crucial in asthma, Zuyderduyn et al. suggested that these cells should be targeted, rather than targeting inflammation or dealing with the symptoms .
Largest Asthma Genetics Study
The largest and most comprehensive study of asthma genetics to date was conducted in 2010 by a consortium of more than a hundred centres worldwide . They ran a GWA study , which genotyped 10,365 persons with asthma and 16,110 unaffected persons to test for association between 582,892 SNPs and asthma. This large study identified genes on chromosomes 2 , 6 , 9 , 15 , 17 , and 22 associated with asthma. The ORMDL3 gene, in particular, was associatedwith childhood onset, whereas the HLA-DQ gene was related to later-onset asthma. Further, the results showed that 38% of all cases of childhood-onset asthma were attributable to a combination of the identified genes.
The study also found an association between serum total IgE and the HLA-DRB1 gene within the class II region of the major histocompatibility complex on chromosome 6. However, this locus was not associated with asthma most of the identified susceptibility loci for asthma were not associated with IgE, suggesting that elevation of serum total IgE has only a minor role in asthma development.
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Prevention And Treatment Of Asthma
There is no way to prevent asthma, even if you start treatment early on after your symptoms develop, says Szefler. Researchers are starting to look at whether using biologic medications containing live bacteria could work to prevent asthma, Szelfer says, “but the results are several years off.”
However, even if you can’t prevent asthma, there are steps you can take to prevent asthma attacks:
- Take all your medications as prescribed. Don’t make any changes without first discussing with your doctor even if your symptoms improve.
- Schedule regular checkups with your doctor. In particular, let your doctor know if you find yourself relying on an inhaler to relieve your symptoms, as this may be a sign that your asthma is not under control.
- Find out what triggers your asthma symptoms and avoid those triggers as much as possible. Common triggers include tobacco smoke or allergens like pollen and dust.
- Get a flu shot. Coming down a respiratory infection can worsen your asthma symptoms and trigger attacks. You can also fight off illness by taking steps to boost your immune system.
Asthma is an ongoing condition and you should “maintain good medical follow-up to keep the disease under control,” Szefler says. You will need to make an individual treatment plan with your doctor, designed to target your symptoms and help avoid your asthma triggers.
Its Difficult To Say For Sure Why People Get Asthma But Thanks To Research Were Clear About Some Of The Risk Factors That Make Asthma More Likely
What causes asthma is different to what triggers asthma:
- The causes are the underlying reasons why someone gets asthma in the first place.
- Triggers are things like dust mites or pollen that can make asthma symptoms worse.
Here we look at what causes asthma, and where its possible for you to lower the risk. The good news is that some of these risk factors are things you can do something about.
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Chapter 3: Is Asthma Inherited
The simple answer to this question is, YES, a tendency to develop asthma is inherited. If one of your biologic parents has or had asthma, then you are morely likely to develop asthma than if he or she did not have asthma. If both of your parents have asthma, you are even more likely to develop asthma than if only one parent has this condition.
Another confirmation that asthma is inherited comes from studies of twins. If one identical twin has asthma, the other twin is more likely to have asthma than when one of two non-identical twin siblings has asthma.
However, the whole story is not as simple as the idea that one either inherits the asthma gene or genes from one’s parents or one does not. For one thing, we know from studies of identical twins that if one twin has asthma, the chances of the other twin developing asthma is only 1 in 3, despite the fact that the inherited information in their genes is identical. For another thing, we know that some people working in certain occupations are more likely to develop asthma than if they had not held those jobs. For instance, if you work in a lumber mill and are exposed day after day to sawdust from certain types of woods, you may develop asthma as a result of this exposure. First, workers experience asthma symptoms only when they breathe in the sawdust, but with time they develop asthma to all the usual stimuli . Sometimes the asthma goes away if the person stops working in the sawmill and sometimes it does not.
Breathing: Normal Airways Vs Asthma Airways
Normal: In someone with optimal lung function, air is inhaled through the nose and mouth, passing through the trachea before moving into the bronchi . The bronchi branch into smaller tubes, ending in many small sacs called alveoli. Its in the alveoli that oxygen is passed to the blood and carbon dioxide is removed.
Asthma: In someone with asthma, the airways are inflamed, and when triggered, can constrict even more, obstructing airflow to the lungs.
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Linkage Followed By Positional Candidate Studies
Identifying genes via linkage studies proved to be quite challenging. Among the > 25 linkage studies reported between 1996 and 2009 , only nine genes were successfully identified by positional candidate studies in linked regions . All but one of these genes were novel at the time, i.e. they had not been considered as asthma âcandidateâ genes prior to their identification through linkage and positional cloning studies.
Candidate Genes And Snps
shows the list of common candidate genes in asthma with their locations derived from a large number of single nucleotide polymorphisms studies. The following are some of the extensively studied candidate genes and SNPs associated with asthma, with special reference to studies in the Indian population:
2. Interleukin-4 : This is located on chromosome 5 at position q31 with 32675 bps, 10 exons and 9 introns. IL-4 is a cytokine secreted by helper T cell type 2 that stimulates the production of IgE and induces eosinophil-mediated attacks against allergens. Chiang et al established that polymorphism in the promoter of the IL-4 is associated with asthma and is a disease modifier in terms of the severity of airway hyper-responsiveness . A total of 16 polymorphisms were identified in the IL4, of which one in the promoter and other on the 5 untranslated region of the IL4 have been identified that influence total serum IgE levels and bronchial hyper-responsiveness. Nagarkati et al indicated that the promoter of the IL4 gene is invariant in Indian population and Bijanzadeh et al reported that there are no significant association between this SNP of the IL-4 and asthma in an Indian population.
6. G-protein-coupled receptor for asthma : This is localized on chromosome 7p with 7 SNPs. A hierarchical genotyping design was used to identify this gene. The data implied that this gene is involved in the pathogenesis of atopy and asthma and may have application in other inflammatory diseases.
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Estimating The Contribution Of The Sentinel Variants To The Heritability Ofasthma Hay Fever And Eczema
Five steps were involved. First, we performed a GWAS of the individualdiseases in the HUNT study, which was not included in the discoverymeta-analysis. The HUNT study is described in greater detail in the .Briefly, based on self-reported questionnaire information, we identified 1,875cases and 16,463 controls for the asthma GWAS 6,939 cases and 12,844 controlsfor the hay fever GWAS and 2,630 cases and 16,131 controls for the eczema GWAS.After quality control filters, we analyzed 7.6 million common variants for association with each individual phenotype. Thegenomic inflation factor for these analyses were 1.049 for asthma,1.078 for hay fever, and 1.041 for eczema. Second, for each of the threediseases, we quantified the overall SNP-based heritabilities with LD scoreregression using a subset of 1.2 millionHapMap SNPs. To obtain a heritability estimate on the liability scale, we setthe population prevalence to be the same as the sample prevalence, given thatthis was a population-based study. Third, we removed the 136 sentinel variants fromthe individual disease GWAS results. Fourth, we re-estimated SNP-basedheritabilities as described for step two, but now using the GWAS results withoutthe 136 top associations. In the fifth and final step, the contribution of the136 sentinel variants towards the heritability of each disease was calculated asthe difference between the SNP-based heritability estimated in steps two and four .
Clinical Heterogeneity And Intermediate Phenotypes
Asthma is not a single disease but rather an umbrella for multiple diseases with similar clinical features, and likely with different genetic and environmental contributors. On the one hand, more precise phenotypic definitions would allow identification of more homogeneous subgroups of patients with asthma and facilitate genetic studies. On other hand, the discovery of asthma and allergy susceptibility loci could provide insights into phenotypic subgroups and ultimately inform the selection of targeted/effective treatment. Because of this clinical heterogeneity and challenge in defining asthma subgroups, intermediate phenotypes that can be measured more objectively are often the focus of genetic studies . These phenotypes include BHR, lung function, serum IgE, allergen skin test response, and blood eosinophil count, as described in . Genetic studies of intermediate phenotypes may ultimately facilitate the discovery of susceptibility genes for asthma or allergic diseases , or they may only identify genes that influence normal variation in the trait itself.
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