Corneal opacity in canine MPS I. Changes after bone marrow transplantation

Corneal opacification associated with glycosaminoglycan (GAG) deposition occurs in canine mucopolysaccharidosis I (MPS I), a deficiency of the lysosomal enzyme alpha-L-iduronidase. In affected dogs corneal lesions appear similar to those in children with the same disease. Transplantation of bone marrow from unaffected littermates was performed in 5 MPS I affected dogs at 5 months of age. In three recipients that became long-term survivors corneal clouding was largely alleviated compared to affected control dogs. In no case, however, did the corneas remain totally clear throughout the course of the study (594, 628 and 1425 days). Light and electron microscopic findings correlated with the clinical impression of partial improvement. Glycosaminoglycan analysis of corneal tissue from two transplant recipients, one normal littermate, and one MPS I-affected, untransplanted dog showed quantitative and qualitative changes in stored GAG following bone marrow transplantation.