title: Classical Scheuermann disease in male monozygotic twins: further support for the genetic etiology hypothesis.
abstract: METHODS
  Classic cases of Scheuermann disease in male monozygotic twins are reported.
  
  
  OBJECTIVE
  To report classic cases of Scheuermann disease or Scheuermann kyphosis in male monozygotic twins, and to discuss the previous two cases of classic Scheuermann disease in monozygotic twins and the genetic etiology theory of Scheuermann kyphosis.
  
  
  BACKGROUND
  The etiology of Scheuermann disease remains unclear. Both genetic and mechanical factors or a combination of the two have been postulated to explain Scheuermann disease. The genetic etiology hypothesis has been explained by an autosomal dominant inheritance pattern. In support of this genetic etiology hypothesis, two cases of Scheuermann disease in monozygotic twins have been reported in the English literature.
  
  
  METHODS
  The criteria of Sørensen and Sachs et al were used to diagnose Scheuermann kyphosis. Clinical examination and lateral spinal radiographs were performed on a male monozygotic twin. Both parents were clinically investigated for signs of a kyphotic deformity. RESULTS Scheuermann disease was noted in both patients at the same vertebral levels. The Cobb angle of the kyphosis was 74 degrees and 48 degrees, respectively. Clinical examination of both parents did not show any kyphotic abnormality.
  
  
  CONCLUSIONS
  These cases of classic Scheuermann disease in monozygotic male twins support the theory that there is a genetic contribution in classic Scheuermann disease.
authors.affiliation: Department of Orthopaedic Surgery, Academic Hospital Maastricht, Maastricht, The Netherlands.
authors.forename: Harm C A
authors.initials: HC
authors.lastname: Graat
authors.forename: Lodewijk W
authors.initials: LW
authors.lastname: van Rhijn
authors.forename: Connie T R M
authors.initials: CT
authors.lastname: Schrander-Stumpel
authors.forename: André
authors.initials: A
authors.lastname: van Ooij
mesh_terms: D000293:Adolescent; D006801:Humans; D007738:Kyphosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology*; D017116:Low Back Pain / Q000209:etiology; D008297:Male; D011859:Radiography; D012544:Scheuermann Disease / Q000175:diagnosis* / Q000209:etiology* / Q000235:genetics; D013904:Thoracic Vertebrae / Q000002:abnormalities / Q000000981:diagnostic imaging; D014430:Twins, Monozygotic