European Journal of Pediatrics

, Volume 156, Issue 3, pp 214–223

Heterogeneity in Schwartz-Jampel chondrodystrophic myotonia

  • A. Giedion
  • E. Boltshauser
  • J. Briner
  • G. Eich
  • G. Exner
  • H. Fendel
  • L. Kaufmann
  • B. Steinmann
  • J. Spranger
  • A. Superti-Furga
MEDICAL GENETICS

DOI: 10.1007/s004310050587

Cite this article as:
Giedion, A., Boltshauser, E., Briner, J. et al. Eur J Pediatr (1997) 156: 214. doi:10.1007/s004310050587

Abstract

The Schwartz-Jampel syndrome (SJS; chondrodystrophic myotonia; McK 255800) is a recessively inherited condition defined by myotonia, short stature, and bone dysplasia. Genetic linkage between SJS and chromosomal region 1q36-34 has been observed in several families, but the gene has not yet been identified. We studied the clinical and radiological features in 81 patients from the literature and 5 own patients trying to identify distinct subgroups. In addition, we tested genetic linkage to the SJS locus on chromosome 1 in one family with two affected sibs. We found that a group of patients have mild skeletal changes which may be secondary consequences of myotonia, while another group of patients appear to have primary bone dysplasia with myotonia. Within this latter group, there are differences in age of manifestation, clinical course and pattern of bone changes. We tentatively isolate three different types of SJS: type 1A, usually recognized in childhood, with moderate bone dysplasia, corresponding to the original descriptions of Schwartz, Jampel and Aberfeld; type 1B, similar to type 1A but recognizable at birth, with more pronounced bone dysplasia resembling Kniest dysplasia; and type 2, manifest at birth, with increased mortality and bone dysplasia resembling Pyle disease. Genetic analysis of the family with two sibs affected by SJS type␣2 showed evidence against linkage to chromosome 1p36-34.

Conclusions SJS is clinically and radiologically heterogeneous. The causes of heterogeneity are not known yet but are likely to include both different mutations at the SJS locus on chromosome 1 and the presence of a second SJS locus. A tentative clinico-radiological classification can be useful for the characterization of patients and the development of genotype-phenotype correlations.

Key words Schwartz-Jampel syndrome Osteochondrodysplasia Myotonia Short stature Genetic linkage 

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • A. Giedion
    • 5
  • E. Boltshauser
    • 5
  • J. Briner
    • 1
  • G. Eich
    • 5
  • G. Exner
    • 2
  • H. Fendel
    • 3
  • L. Kaufmann
    • 5
  • B. Steinmann
    • 5
  • J. Spranger
    • 4
  • A. Superti-Furga
    • 5
  1. 1.Institute of Clinical Pathology, University Hospital, CH-8091 Zurich, SwitzerlandCH
  2. 2.Orthopaedic Clinic Balgrist, University of Zürich, SwitzerlandCH
  3. 3.Von Haunersches Kinderspital, University of München, GermanyDE
  4. 4.Kinderklinik, Johnannes Gutenberg University, Mainz, GermanyDE
  5. 5.University Children's Hospital, Steinwiesstrasse 75, CH-8032 Zurich, Switzerland Fax: +41-1-266-7171 Email: asuperti @hispi.unizh.chCH