Genetic Susceptibility to Childhood Respiratory IIlness in Mexico City
Condition: Asthma
MeSH terms: Genetic Predisposition to Disease
Study type: Observational

Summary: 
      We propose to add a collection of genetic material to a clinical trial of anti-oxidant
      supplementation for the amelioration of asthma in 7-12 year olds being conducted at a public
      pediatric hospital in Mexico City. The anti-oxidant study has been approved by the
      Institutional Review Board of the National Institute of Public Health in Mexico City and is
      scheduled to begin in September 1998. The purpose of this add-on study is to examine genetic
      polymorphisms that may be related to asthma. Asthma cases will be compared with their parents
      as controls. In partaicular, we will save the buffy coat from the blood collection being done
      on the asthmatic child for measurements of plasma micronutrients in the anti-oxidant trial
      for extraction of DNA. This part of the sample would otherwise be discarded. In addition, we
      will enroll the parents of the asthmatic child as controls for the child. From the parents,
      either a 10 ml blood sample or if they prefer, a sample of buccal cells will be collected.
      Although our current plan is to compare the asthmatic child to the parents using statistical
      methods based on the "transmission disequilibrium test" because research into various family
      designs for candidate gene studies is rapidly evolving and various sibling control sample
      strategies have been discussed, we would also like to collect a genetic sample on as many of
      the child's siblings as possible with priority given to those closest in age. This will
      enhance the future usefulness of the samples. We anticipate enrolling approximately 200
      families....
    

Detailed description: 
      We propose to add a collection of genetic material to a clinical trial of anti-oxidant
      supplementation for the amelioration of asthma in 7-12 year olds being conducted at a public
      pediatric hospital in Mexico City. The anti-oxidant study has been approved by the
      Institutional Review Board of the National Institute of Public Health in Mexico City and is
      scheduled to begin in September 1998. The purpose of this add-on study is to examine genetic
      polymorphisms that may be related to asthma. Asthma cases will be compared with their parents
      as controls. In particular, we will save the buffy coat from the blood collection being done
      on the asthmatic child for measurements of plasma micronutrients in the anti-oxidant trial
      for extraction of DNA. This part of the sample would otherwise be discarded. In addition, we
      will enroll the parents of the asthmatic child as controls for the child. From the parents,
      either a 10 ml blood sample or if they prefer, a sample of buccal cells will be collected.
      Although our current plan is to compare the asthmatic child to the parents using statistical
      methods based on the "transmission disequilibrium test" because research into various family
      designs for candidate gene studies is rapidly evolving and various sibling control sample
      strategies have been discussed, we would also like to collect a genetic sample on as many of
      the child's siblings as possible with priority given to those closest in age. This will
      enhance the future usefulness of the samples. We anticipate enrolling approximately 200
      families.
    

Observational model: Family-Based
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Asthmatic children registered at the allergy clinic of the Pediatric Hospital Frederico
        Gomez in Mexico City and their biological parents.
      
Keywords: Asthma; Mexico; Triads; Polymorphism; Genetic Predisposition