A variability in DNA sequences among patients with the
same condition may influence their response to drug therapy
What is asthma?
Asthma is a chronic persistent inflammatory
condition of the airways characterized by exacerbations of coughing, wheezing,
chest tightness and difficult breathing that are usually reversible, but
that can be severe and sometimes fatal.
Increased prevalence of asthma among first-degree
relatives of asthmatic subjects and among monozygotic compared to dizygotic
twins, has long suggested a genetic component to the condition.
Asthma is now recognised to be a result of
the interaction of environmental and genetic factors in genetically susceptible
individuals. It is a multifactorial and polygenic disease, where
several genes and environmental conditions contribute to produce the clinical
symptoms.
The incidence of asthma has increased significantly
throughout Europe during the last 10 years.
Genetics of asthma
Two approaches are mainly being used by researchers
to perform genetic studies on asthma. The genome screen
approach aims to scan the whole human genome for asthma susceptibility
genes. The candidate gene approach aims to examine
polymorphisms within identified potential contributory genes, for association
with the disease.
The genome screen approach has
helped to identify areas within the genome which appear to be linked to
specific characteristics of asthma. Candidate gene
studies have provided specific information on genetic polymorphisms, which
may either affect the severity of the disease or alter its response to
pharmacological treatment.
Research aspects
Department of Clinical Pharmacology
and Therapeutics, University of Malta, Laboratory of Molecular Genetics,
Unversity of Malta, Department of Physiology and Biochemistry, University
of Malta, Department of Therapeutics, Institute of Cell Signalling, Queen's
Medical Centre, University of Nottingham, UK
Pharmacogenetic research is currently
underway in order to identify and study polymorphisms within specific candidate
genes for asthma.
Functional studies of candidate gene mutations
will be subsequently undertaken
Potential benefits
Pharmacogenetic approaches to asthma research
may potentially alter the way in which patients are cared for in the future.
The identification and study of novel mutations
will contribute to a better understanding of the variation in responses
to drug therapy among asthma patients.
The ability to routinely screen for important
polymorphisms which alter the pharmacologic response to specific drug therapy,
will have important implications in deciding on a suitable therapeutic
regimen based on a patient's own genotype.