The clinical, biochemical and molecular characteristics of Ehlers-Danlos syndrome type IV are reviewed. The numerous clinical manifestations result from the generalized and excessive tissue fragility characteristic for this disorder. The variability in cutaneous involvement may hamper recognition of the condition and requires careful clinical examination. Clinical diagnosis can be confirmed by demonstration of a collagen type III defect. The severity of the phenotype appears to be related mainly to the intrinsic stability of mutant type III collagen protein and its disturbing effect on normal collagen fibrillogenesis in the extracellular matrix.