Allergy and Genes go hand-in-hand, say Hyderabad scientists

June 26, 2007
By Syed Akbar
Hyderabad, June 25: A group of city scientists has identified the genetic link in Indian population to over-allergic reactions (atopy) and asthma.
Researchers at the city-based Centre for Cellular and Molecular Biology, Saboo Hospital and Research Centre, Osmania Medical College and Niloufer Children's Hospital came out with a genetic analysis of bronchial asthma in Indian population elucidating the complex genetic regulation of the disease including atopy. The study will help in better understanding of the root causes of these chronic diseases and effective diagnosis and treatment.
The research work gains significance in the backdrop of increasing instances of asthma and active allergic problems in the country. So far, researchers have been looking at asthma from environmental point of view and for the first time in India, the city researchers have turned their concentration on the genetic aspects of this complex polygenic disease. Asthma is commonly associated with familial atopic syndrome and increased levels of total IgE (immunoglobulins E).
The study carried out by GR Chandak, M Mohammed Idris, Sandeep Saboo, GS Ramalaxmi and others points out asthma and allergy are not inherited as single gene disorders and do not follow a simple Mendelian inheritance. A complex interaction between environmental and genetic factors produces the disease susceptibility and expression.
Identifying specific genetic polymorphisms that influence asthma and atopic phenotypes will also help in better screening of the "at risk" population and pave the way for extension of these markers in different population groups in the country. It may also lead to a novel strategy to modulate the course of this disease or identify better therapeutic modalities.
The city researchers investigated the association of polymorphisms and extended haplotype in genes (IL4 and IL4RA) with atopy and asthma in the Indian population and attempted to study whether genotypic and haplotypic differences can account for the phenotypic variations in atopic and non-atopic asthmatic individuals.
The probands (individual subjects of a genetic study) and control subjects were recruited based on the evaluation of clinical and family history using a standardised questionnaire following the guidelines of American Thoracic Society. They were examined for a self-reported history of breathlessness, wheeze, allergic rhinitis and eczema and confirmed by various pulmonary function tests.