title: Surfactant protein A gene locus and respiratory distress syndrome in Finnish premature twin pairs.
abstract: BACKGROUND
  Surfactant protein A (SP-A) polymorphisms are associated with susceptibility to respiratory distress syndrome (RDS). According to present hypothesis the association between SP-A polymorphisms and RDS may not be applicable to the entire population of premature infants.
  
  
  OBJECTIVE
  The present study was designed to evaluate the associations between SP-A allelic variants and RDS in a population consisting of 198 premature twin pairs.
  
  
  METHODS
  Genotype analysis of the SP-A1 and SP-A2 genes and twin zygosity definition were carried out.
  
  
  RESULTS
  The main SP-A1 allele 6A2 (P = 0.030), genotype 6A2/6A2 (P = 0.0042) and haplotype 6A2-1A(0) (P = 0.016) were over-represented in healthy premature twin infants compared to RDS twins. The homozygous genotype 6A2/6A2 was over-represented in twin pairs of whom both were healthy compared to twins concordant for RDS (odds ratio 0.18, confidence intervals 0.06-0.6, P = 0.0016) and born between 32 and 36 weeks. 6A2/6A2 was also overrepresented in healthy twin pairs with birth weight sum higher than the median (OR 0.15, CI 0.04-0.6, P = 0.0025).
  
  
  CONCLUSIONS
  In twins, the association between SP-A polymorphism and RDS is different from that seen in premature singleton infants. The factor associated with SP-A genotype-specific susceptibility to RDS appears to be related to the size of uterus and the length of gestation at birth.
authors.affiliation: Central Hospital of Southern Ostrobothnia, Seinäjoki, Finland.
authors.forename: Riitta
authors.initials: R
authors.lastname: Marttila
authors.forename: Ritva
authors.initials: R
authors.lastname: Haataja
authors.forename: Mika
authors.initials: M
authors.lastname: Rämet
authors.forename: Marja-Leena
authors.initials: ML
authors.lastname: Pokela
authors.forename: Outi
authors.initials: O
authors.lastname: Tammela
authors.forename: Mikko
authors.initials: M
authors.lastname: Hallman
mesh_terms: D016000:Cluster Analysis; D005260:Female; D005387:Finland; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D014644:Genetic Variation; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D016015:Logistic Models; D008297:Male; D011110:Polymorphism, Genetic / Q000235:genetics*; D037662:Pulmonary Surfactant-Associated Protein A / Q000235:genetics*; D012127:Respiratory Distress Syndrome, Newborn / Q000235:genetics* / Q000473:pathology; D014599:Uterus / Q000473:pathology*
chemical_list: D037662:Pulmonary Surfactant-Associated Protein A