Continued neurocognitive development and prevention of cardiopulmonary complications after successful BMT for I-cell disease: a long-term follow-up report.

I-cell disease or mucolipidosis type II, a rare inherited storage disorder of lysosomal enzyme localization, is characterized by dysostosis multiplex, progressive severe psychomotor retardation and death by 5-8 years from congestive heart failure and recurrent pulmonary infections. A 19-month old girl with I-cell disease received a bone marrow transplant (BMT) from an HLA-identical carrier brother. At the age of 7 years, 5 years after BMT, she has no history of respiratory infections. Her cardiac function remains normal with a shortening fraction of 47%, and she continues to gain neurodevelopmental milestones, albeit at a very slow rate. Musculoskeletal deformities have worsened despite BMT. This is the first report describing neurodevelopmental gains and prevention of cardiopulmonary complications in I-cell disease after BMT.