The role of type III collagen in spontaneous cervical arterial dissections.

A case-control study was carried out to investigate whether type III collagen deficiency plays a role in the pathogenesis of spontaneous cervical arterial dissections. In 16 patients with spontaneous cervical arterial dissections and in 41 healthy controls, protein analysis of type III collagen (ratio of type III/type I collagen) was performed. Furthermore, single-stranded conformation polymorphism/heteroduplex analysis was used to investigate the type III collagen gene in the 16 patients with spontaneous cervical dissections to detect mutations. The ratios of type III/type I collagen in the controls ranged from 5.5 to 19.8% (median, 10%). The ratios of type III/type I collagen in the patients with spontaneous cervical arterial dissections ranged from 3.2 to 17.9% (median, 9.3%). Two patients had a low ratio of type III/type I collagen (<5.5%). No abnormalities suggesting a mutation in the gene of type III collagen were demonstrated in any of the 16 patients. Our findings are in keeping with the hypothesis that a reduced production of type III collagen may contribute to the formation of spontaneous cervical arterial dissections in some patients. The absence of a responsible mutation indicates that the coding sequence of the type III collagen gene is not involved.