Transkaryotic Therapies Inc announced the issuance of a third U.S. patent involving the lysosomal enzyme alpha-L-iduronidase (IDUA), which is deficient in persons suffering from mucopolysaccharidosis type I (MPS I), also referred to as Hurler syndrome, Hurler-Scheie syndrome, or Scheie syndrome. TKT's patent estate involving IDUA relates to compositions and methods for the diagnosis and treatment of MPS I. The patent claims of U.S. Patent No. 6,524,835 issued today by the U.S. Patent and Trademark Office cover compositions that encode human IDUA as well as vectors and host cells useful in the production of human IDUA.

TKT has a growing intellectual property estate in the area of MPS disorders that results from its collaboration with Dr. John Hopwood of the Women and Children's Hospital in Australia. This collaboration has resulted in a diverse patent portfolio of 12 U.S. patents and some foreign equivalents covering three of the six MPS diseases -- MPS I, II and III -- all of which are exclusively licensed to TKT.

"We are proud to be working on rare diseases with one of the world's great researchers, and we are pleased that the Patent Office has again recognized the innovative nature of his work," said Michael J. Astrue, President and Chief Executive Officer of TKT.

MPS I is a rare inherited genetic disorder caused by deficient activity of the protein alpha-L-iduronidase (IDUA). IDUA is present in the lysosomes of cells, where it helps break down large biomolecules called mucopolysaccharides. In patients affected by MPS I, these mucopolysaccharides accumulate in organs and tissues of the body, particularly in the central nervous system, liver, spleen, heart and skeleton, ultimately leading to cell death and progressive tissue and organ damage. It is estimated that 1 in 25,000 births will result in some form of MPS in the United States.