title: A study of collectin genes in spontaneous preterm birth reveals an association with a common surfactant protein D gene polymorphism.
abstract: BACKGROUND
  Preterm birth is the major cause of mortality and morbidity in neonates. Intrauterine infection and/or inflammatory response are evident in 60-70% of spontaneous preterm births (SPTBs). Genetic factors significantly increase this risk. However, the genetic background associated with SPTB is poorly understood. Surfactant protein (SP) A, SP-D, and mannose-binding lectin (MBL) are structurally and functionally related collectins that bind pathogen-associated molecular patterns, and mostly suppress innate immune responses.
  
  
  RESULTS
  We detected an overrepresentation of the methionine allele of the SFTPD gene (encoding SP-D) Met31Thr polymorphism in preterm infants as compared to term infants. This association was highly significant in infants of families with recurrent SPTBs (P = 0.001, odds ratio = 1.65, 95% confidence interval = 1.22-2.22); however, there was no such association with SFTPD in the mothers of these infants. Polymorphism of the genes encoding SP-A and MBL did not influence the risk of SPTB.
  
  
  CONCLUSIONS
  Our results suggest that the fetal SFTPD Met31Thr polymorphism plays a significant role in genetic predisposition to SPTB. We propose that fetal immune responses influence sensitivity to preterm labor-inducing signals.
  
  
  METHODS
  Genes encoding SP-A, SP-D, and MBL were investigated as potential candidates for association with SPTB in a population of preterm singleton infants (n = 406) and their mothers (n = 308), and in mothers with term deliveries (n = 201) and their infants (n = 201), all originating from northern Finland.
authors.affiliation: Department of Pediatrics, Institute of Clinical Medicine, University of Oulu, Oulu, Finland. minna.k.karjalainen@oulu.fi
authors.forename: Minna K
authors.initials: MK
authors.lastname: Karjalainen
authors.forename: Johanna M
authors.initials: JM
authors.lastname: Huusko
authors.forename: Anu
authors.initials: A
authors.lastname: Tuohimaa
authors.forename: Aino
authors.initials: A
authors.lastname: Luukkonen
authors.forename: Ritva
authors.initials: R
authors.lastname: Haataja
authors.forename: Mikko
authors.initials: M
authors.lastname: Hallman
mesh_terms: D000293:Adolescent; D000328:Adult; D037222:Collectins / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005865:Gestational Age; D006239:Haplotypes; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000235:genetics; D015810:Linkage Disequilibrium; D037601:Mannose-Binding Lectin / Q000235:genetics; D008715:Methionine / Q000235:genetics; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011247:Pregnancy; D047928:Premature Birth / Q000235:genetics*; D037662:Pulmonary Surfactant-Associated Protein A / Q000235:genetics; D037663:Pulmonary Surfactant-Associated Protein D / Q000235:genetics*; D013912:Threonine / Q000235:genetics; D055815:Young Adult
chemical_list: D037222:Collectins; C445619:MBL2 protein, human; D037601:Mannose-Binding Lectin; D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D; D013912:Threonine; D008715:Methionine