Genetic admixture and asthma-related phenotypes in Mexican American and Puerto Rican asthmatics.
Genetic association studies in admixed populations may be biased if individual ancestry varies within the population and the phenotype of interest is associated with ancestry. However, recently admixed populations also offer potential benefits in association studies since markers informative for ancestry may be in linkage disequilibrium across large distances. In particular, the enhanced LD in admixed populations may be used to identify alleles that underlie a genetically determined difference in a phenotype between two ancestral populations. Asthma is known to have different prevalence and severity among ancestrally distinct populations. We investigated several asthma-related phenotypes in two ancestrally admixed populations: Mexican Americans and Puerto Ricans. We used ancestry informative markers to estimate the individual ancestry of 181 Mexican American asthmatics and 181 Puerto Rican asthmatics and tested whether individual ancestry is associated with any of these phenotypes independently of known environmental factors. We found an association between higher European ancestry and more severe asthma as measured by both forced expiratory volume at 1 second (r=-0.21, p=0.005) and by a clinical assessment of severity among Mexican Americans (OR: 1.55; 95% CI 1.25 to 1.93). We found no significant associations between ancestry and severity or drug responsiveness among Puerto Ricans. These results suggest that asthma severity may be influenced by genetic factors differentiating Europeans and Native Americans in Mexican Americans, although differing results for Puerto Ricans require further investigation.
Salari
Keyan
K
Department of Medicine, University of California, San Francisco, California 94143-1732, USA.
Choudhry
Shweta
S
Tang
Hua
H
Naqvi
Mariam
M
Lind
Denise
D
Avila
Pedro C
PC
Coyle
Natasha E
NE
Ung
Ngim
N
Nazario
Sylvette
S
Casal
Jesus
J
Torres-Palacios
Alfonso
A
Clark
Suzanne
S
Phong
Angie
A
Gomez
Ivan
I
Matallana
Henry
H
Pérez-Stable
Eliseo J
EJ
Shriver
Mark D
MD
Kwok
Pui-Yan
PY
Sheppard
Dean
D
Rodriguez-Cintron
William
W
Risch
Neil J
NJ
Burchard
Esteban González
EG
Ziv
Elad
E
D000293:Adolescent; D001249:Asthma / Q000208:ethnology* / Q000235:genetics*; D001993:Bronchodilator Agents / Q000627:therapeutic use; D002648:Child; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects / Q000235:genetics; D005819:Genetic Markers; D005838:Genotype; D006630:Hispanic or Latino / Q000235:genetics*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000235:genetics; D015810:Linkage Disequilibrium / Q000235:genetics*; D008297:Male; D017058:Mexican Americans / Q000235:genetics*; D010641:Phenotype; D011647:Puerto Rico / Q000208:ethnology; D012720:Severity of Illness Index
D001993:Bronchodilator Agents; D005819:Genetic Markers; D007073:Immunoglobulin E