Two cases of Kniest's Syndrome with different evolution are reported. One diedbefore reaching the fourth month of life, while the other is still alive at 6 years of age. Theetiology and pathogenesis of this syndrome are discussed, paying special attention to the typeII colagen. A defect of this colagen would induce physes and epiphyses alterations, dwarfismand ocular lesions. The chondrocostal cartilage in one case and accesory cartilage of iliac bonein the other were biopsied, showing in both cases cytoplasmatic vacuolization of chondrocytes.The differential diagnosis with metatropic dwarfism and disegmentarie dysplasia, in its midlerfrom or Rolland-Desbuqois type, is presented.

Two cases of Kniest's Syndrome with different evolution are reported. One diedbefore reaching the fourth month of life, while the other is still alive at 6 years of age. Theetiology and pathogenesis of this syndrome are discussed, paying special attention to the typeII colagen. A defect of this colagen would induce physes and epiphyses alterations, dwarfismand ocular lesions. The chondrocostal cartilage in one case and accesory cartilage of iliac bonein the other were biopsied, showing in both cases cytoplasmatic vacuolization of chondrocytes.The differential diagnosis with metatropic dwarfism and disegmentarie dysplasia, in its midlerfrom or Rolland-Desbuqois type, is presented.