Linkage of a polymorphic marker for the type III collagen gene (COL3A1) to atypical autosomal dominant Ehlers-Danlos syndrome type IV in a large Belgian pedigree.

We have examined a large family in which eleven members have a form of autosomal dominant Ehlers-Danlos syndrome type IV. Analysis of fibroblast cultures from affected individuals showed a partial deficiency of type III collagen production. The protein produced was, however, normal in all aspects examined. Using a restriction site polymorphism associated with the structural gene for human type III collagen (COL3A1), we have found tight linkage between the low frequency polymorphic allele and the clinical expression of the disease (lod = 3.86 at 0 = 0), identifying the type III collagen gene as the disease locus.