title: Aquaporin-4 polymorphisms and brain/body weight ratio in sudden infant death syndrome (SIDS).
abstract: BACKGROUND
  Failure in the regulation of homeostatic water balance in the brain is associated with severe cerebral edema and increased brain weights and may also play an important role in the pathogenesis of sudden infant death syndrome (SIDS). We genotyped three single-nucleotide polymorphisms in the aquaporin-4 water channel-encoding gene (AQP4), which were previously shown to be associated with (i) SIDS in Norwegian infants (rs2075575), (ii) severe brain edema (rs9951307), and (iii) increased brain water permeability (rs3906956). We also determined whether the brain/body weight ratio is increased in SIDS infants compared with sex- and age-matched controls.
  
  
  METHODS
  Genotyping of the three AQP4 single-nucleotide polymorphisms was performed in 160 Caucasian SIDS infants and 181 healthy Swiss adults using a single-base extension method. Brain and body weights were measured during autopsy in 157 SIDS and 59 non-SIDS infants.
  
  
  RESULTS
  No differences were detected in the allelic frequencies of the three AQP4 single-nucleotide polymorphisms between SIDS and adult controls. The brain/body weight ratio was similarly distributed in SIDS and non-SIDS infants.
  
  
  CONCLUSIONS
  Variations in the AQP4 gene seem of limited significance as predisposing factors in Caucasian SIDS infants. Increased brain weights may only become evident in conjunction with environmental or other genetic risk factors.
authors.affiliation: Institute of Legal Medicine, Forensic Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Studer
authors.affiliation: Institute of Legal Medicine, Forensic Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Christine
authors.initials: C
authors.lastname: Bartsch
authors.affiliation: Institute of Legal Medicine, Forensic Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Cordula
authors.initials: C
authors.lastname: Haas
mesh_terms: D051401:Aquaporin 4 / Q000235:genetics*; D001344:Autopsy; D001835:Body Weight; D001921:Brain / Q000473:pathology*; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009929:Organ Size; D020641:Polymorphism, Single Nucleotide; D013398:Sudden Infant Death / Q000235:genetics* / Q000473:pathology*
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4