- A single base mutation in the gene for type III collagen (COL3A1) converts glycine 847 to glutamic acid in a family with Ehlers-Danlos syndrome type IV. An unaffected family member is mosaic for the mutation. Richards, A.J., Ward, P.N., Narcisi, P., Nicholls, A.C., Lloyd, J.C., Pope, F.M. Hum. Genet. (1992)