Well-defined clinical presentation of Ehlers-Danlos syndrome in patients with tenascin-X deficiency: a report of four cases.

The Ehlers-Danlos syndrome (EDS) is a clinically and genetically heterogeneous group of inherited connective tissue disorders. The six major, well-defined, subtypes are classified according to diagnostic criteria, formalized in the Villefranche revised nosology. Shortly after the publication of these criteria in 1998, a further distinct type of EDS, the tenascin-X (TNX)-deficient type EDS, was reported. The phenotype of this largely unknown type of EDS resembles the phenotype of the classical type of EDS, but its inheritance is autosomal recessive and wound healing is normal; hence, no atrophic scars are present. The clinical diagnosis can be confirmed by the absence of TNX in the serum and by mutation analysis of the TNXB gene. Because the TNX-deficient type EDS is rare and not included in the current diagnostic criteria, this diagnosis is often delayed or even overlooked. Here, we describe four cases which improve the clinical recognition of this type of EDS.