Respiratory symptoms among infants at risk for asthma: association with surfactant protein A haplotypes.
BACKGROUND
We examined the association between single nucleotide polymorphisms (SNPs) in loci encoding surfactant protein A (SFTPA) and risk of wheeze and persistent cough during the first year of life among a cohort of infants at risk for developing asthma.


METHODS
Between September 1996 and December 1998, mothers of newborn infants were invited to participate if they had an older child with clinician-diagnosed asthma. Each mother was given a standardized questionnaire within 4 months of her infant's birth. Infant respiratory symptoms were collected during quarterly telephone interviews at 6, 9 and 12 months of age. Due to the association of SFTPA polymorphisms and race/ethnicity, analyses were restricted to 221 white infants for whom whole blood and respiratory data were available. Ordered logistic regression models were used to examine the association between respiratory symptom frequency and SFTPA haplotypes.


RESULTS
The 6A allele haplotype of SFTPA1, with an estimated frequency of 6% among our study infants, was associated with an increased risk of persistent cough (OR 3.69, 95% CI 1.71, 7.98) and wheeze (OR 4.72, 95% CI 2.20, 10.11). The 6A/1A haplotype of SFTPA, found among approximately 5% of the infants, was associated with an increased risk of persistent cough (OR 3.20, 95% CI 1.39, 7.36) and wheeze (OR 3.25, 95% CI 1.43, 7.37).


CONCLUSIONS
Polymorphisms within SFTPA loci may be associated with wheeze and persistent cough in white infants at risk for asthma. These associations require replication and exploration in other ethnic/racial groups.
Pettigrew
Melinda M
MM
Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, CT, USA. melinda.pettigrew@yale.edu
Gent
Janneane F
JF
Zhu
Yong
Y
Triche
Elizabeth W
EW
Belanger
Kathleen D
KD
Holford
Theodore R
TR
Bracken
Michael B
MB
Leaderer
Brian P
BP
D000483:Alleles; D001249:Asthma / Q000175:diagnosis / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D003371:Cough; D005260:Female; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D020641:Polymorphism, Single Nucleotide; D037662:Pulmonary Surfactant-Associated Protein A / Q000235:genetics*; D012135:Respiratory Sounds; D012307:Risk Factors
D037662:Pulmonary Surfactant-Associated Protein A; C445842:SFTPA1 protein, human; C445843:SFTPA2 protein, human