, a rare, life-threatening disease caused by a deficiency in a lysosomal enzyme. The hereditary, progressive illness causes mental retardation, poor vision and stiffness in the joints.

Tomoki's only chance of getting better is to have a bone marrow or blood transplant from an umbilical cord, but his father has refused because both procedures come with serious risks and may not even work.

But there are new drugs that can ease MPS symptoms and possibly even partially reverse the disease. They have been developed, and several approved for sale, in the United States and Europe, but are not available in Japan.

Earlier this month, the Japanese branch of U.S.-based drug maker Genzyme Corp. began clinical trials on laronidase in Japan -- the result of lobbying by the families of MPS patients to have the sluggish drug-approval process changed.