Asthma is a complex, heterogeneous and chronic airway inflammatory disease with
different clinical phenotypes caused by diverse triggers and pathophysi
ological mechanisms.
Asthma heritability has
been
established in many genetic studies but it is evident that only
genetic elements are not responsible for the development of asthma.
Increasing rate of
asthma incidence during past decades has implicated the
role of epigenetics in development
of asthma.
Environmental factors perform as initiator signals through epigenetic mechanisms.
Three
epigenetic mechanisms have been identified, including DNA methylation, histone
modifications, and small noncoding RNAs.
These mechanisms regulate the immune responses and inflammatory genes expression in
asthma and allergy.
This review explains the role of epigenetic modifications in controlling
Th2 response and IgE production in asthma and also briefly overviews the role o
f
environmental factors such as pollutions, allergens, prenatal exposures and diet in developing
asthma.
Recognizing environmental risk factors and their effects on epigenetic mechanisms would
be of great interest for prognostic and preventive aspect in t
reatment of asthma.