Classical Scheuermann Disease in Male Monozygotic Twins: Further Support for the Genetic Etiology Hypothesis

Study Design. Classic cases of Scheuermann disease in male monozygotic twins are reported. Objectives. 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. Summary of Background Data. 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° and 48°, 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.