title: How Normal is a 'Normal' Heart in Fetuses and Infants with Down Syndrome?
abstract: BACKGROUND
  Congenital heart disease is present in 44-56% of fetuses with Down syndrome (DS). There are, however, signs that hearts in DS without apparent structural heart defects also differ from those in the normal population. We aimed to compare the atrioventricular (AV) septum and valves in 3 groups: DS without AV septal defect (DS no-AVSD), DS with AVSD (DS AVSD) and control hearts.
  
  
  METHODS
  The ventricular septum, membranous septum and AV valves were examined and measured in histological sections of 15 DS no-AVSD, 8 DS AVSD and 34 control hearts. In addition, the ventricular septum length was measured on ultrasound images of fetal (6 DS AVSD, 9 controls) and infant (10 DS no-AVSD, 10 DS AVSD, 10 controls) hearts.
  
  
  RESULTS
  The membranous septum was 3 times larger in DS no-AVSD fetuses compared to control fetuses, and valve dysplasia was frequently (64%) observed. The ventricular septum was shorter in patients with DS both with and without AVSD, as compared to the control group.
  
  
  CONCLUSIONS
  DS no-AVSD hearts are not normal as they have a larger membranous septum, shorter ventricular septum and dysplasia of the AV valves as compared to control hearts.
authors.affiliation: Department of Anatomy and Embryology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Emmeline
authors.initials: E
authors.lastname: Calkoen
authors.forename: Bauke
authors.initials: B
authors.lastname: Adriaanse
authors.forename: Monique
authors.initials: M
authors.lastname: Haak
authors.forename: Margot
authors.initials: M
authors.lastname: Bartelings
authors.forename: Adam
authors.initials: A
authors.lastname: Kolesnik
authors.forename: Cezary
authors.initials: C
authors.lastname: Niszczota
authors.forename: John
authors.initials: J
authors.lastname: van Vugt
authors.forename: Arno
authors.initials: A
authors.lastname: Roest
authors.forename: Nico
authors.initials: N
authors.lastname: Blom
authors.forename: Adriana
authors.initials: A
authors.lastname: Gittenberger-de Groot
authors.forename: Monique
authors.initials: M
authors.lastname: Jongbloed
mesh_terms: D016022:Case-Control Studies; D004314:Down Syndrome / Q000000981:diagnostic imaging / Q000473:pathology*; D004452:Echocardiography; D005318:Fetal Heart / Q000000981:diagnostic imaging / Q000473:pathology*; D006351:Heart Valves / Q000000981:diagnostic imaging / Q000473:pathology*; D053823:Hedgehog Proteins / Q000378:metabolism; D006801:Humans; D009206:Myocardium / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D054088:Ventricular Septum / Q000000981:diagnostic imaging / Q000473:pathology*; D000071676:Zinc Finger Protein GLI1
chemical_list: C400551:GLI1 protein, human; D053823:Hedgehog Proteins; C509239:SHH protein, human; D014157:Transcription Factors; D000071676:Zinc Finger Protein GLI1