Genetic Factors That Influence Chronic Obstructive Pulmonary Disease in Hispanics

DESIGN NARRATIVE:

This study will concentrate on a genetically isolated Hispanic population with a high prevalence of COPD living in the Central Valley of Costa Rica. Nine hundred individuals from descendants of the Costa Rican Central Valley founder population will be enrolled. To identify regions of the genome that are likely to contain genetic determinants of COPD-related phenotypes in this population, the study will collect phenotypic and genotypic data on 30 large families with a history of moderate to severe COPD that have multiple individuals affected with smoking-related airflow obstruction. A genome scan will be conducted on these individuals using short-tandem repeat (STR) markers. Linkage analysis will be performed on 6 COPD-related phenotypes, which will include the following: 1) chronic bronchitis; 2) airflow obstruction; 3) forced expiratory volume in one second (FEV1); 4) FEV1/FVC[forced vital capacity];5) bronchodilator responsiveness; and 6) total serum immunoglobulin E. Within genomic regions demonstrating linkage to COPD-related phenotypes in the genome scan, narrowly spaced STR markers will be genotyped and tested for linkage between these markers and COPD-related phenotypes. Within selected genomic regions, the association will be tested between single nucleotide polymorphisms (SNPs) in candidate genes and COPD-related phenotypes. By enrolling a large number of participants of a genetically isolated population and utilizing a family-based study design, this study should be able to address an important yet unstudied issue: the genetic influences on the expression of the COPD phenotype in Hispanics.

Inclusion criteria

• COPD
• Reduced FEV1 after administration of bronchodilator (less than or equal to 60% of predicted value)
• At least six great-grandparents born in the Central Valley of Costa Rica
• At least one sibling with a history of smoking (10 or more packs per year)

Exclusion criteria

• Chronic respiratory disorder other than COPD (as determined by a questionnaire and high-resolution CT chest scan)
• Severe alpha 1-antitrypsin deficiency