Type III Ehlers-Danlos syndrome: correlations among clinical signs, ultrasound, and histologic findings in a study of 35 cases

Background Patients with type III Ehlers-Danlos syndrome show hypermobile joints, luxation, and minimal atrophic scars. The disease has an incidence of 9-16% and the molecular defect that underlies this subtype is unknown. In order to widen diagnostic investigations in type III Ehlers-Danlos syndrome, skin and articular areas were studied by ultrasound (US) test. Methods Thirty-five patients, 20 women and 15 men. aged from 18 to 25 years, with type III Ehlers-Danlos syndrome were enrolled in this study. Patients showed hypermobile joints (35 cases), minimal atrophic wrinkled scars (35 cases), and a few ice-pick acne scars. Hypermobility of phalangeal joints was studied by means of the Beighton scoring system and by a US test (performed by Sonora Logic 400 MD unit with 10 MHz probe). The following US parameters were considered: the distance of the intra-articular space and the thicknesses of the extensor tendon and of the overhanging dermis and subcutis. Results US reports showed an increase in distance of the intra-articular space and a reduction in the thickness of the extensor tendon and of the dermis and subcutis covering it. The dermis showed high and homogeneous echogenicity with irregular hyperechogenic lines. Conclusions The Beighton scoring system, the US findings, and the aspect and diameter of the scars suggested that the disease can be divided into three different stages which allow the correlation, over progressive intervals of values, of the articular hypermobility and atrophic wrinkled scars. Our results showed that US test is able to confirm the clinical diagnosis and to evaluate the seriousness of hypermobile joints.