1. ^*Department of Dermatology, University Medical Center, St Radboud Nijmegen, Nijmegen, The Netherlands
2. ^†Department of Biochemistry, University Medical Center, St Radboud Nijmegen, Nijmegen, The Netherlands
3. ^‡Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO, USA
4. ^§Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
5. ^¶Department of Pediatrics, University of California at San Francisco, CA, USA

Correspondence: Manon Zweers, Department of Dermatology, University Medical Center, St Radboud Nijmegen, PO Box 9101, 6500 HB Nijmegen, The Netherlands Email: m.zweers@derma.umcn.nl

Received 27 February 2003; Revised 17 October 2003; Accepted 10 November 2003.

Abstract

Deficiency of the extracellular matrix protein tenascin-X (TNX) was recently described as the molecular basis of a new, recessive type of Ehlers–Danlos syndrome. Here we report gross abnormalities of the elastic fibers and microfibrils in the dermis of these patients, and reduced dermal collagen content, as determined by quantitative image analysis. The ascending, fine elastic fibers in the papillary dermis were absent or inconspicuous and had few branches. The coarse elastic fibers of the reticular dermis were fragmented and clumped. At the ultrastructural level, irregular and immature elastin fibers and fibers devoid of microfibrils were observed. In TNX-deficient patients the dermal collagen density was reduced, but no structural abnormalities in the collagen fibrils were found. These findings suggest that both elastic fiber abnormalities and reduced collagen content contribute to the observed phenotype in TNX-deficient patients.