A staging system for infantile Krabbe disease to predict outcome after unrelated umbilical cord blood transplantation

OBJECTIVE. Infantile Krabbe disease, a rare neurodegenerative disorder that leads to rapid demyelination, dysmyelination, and death in the first 2 years of life, is responsive to treatment with umbilical cord blood transplantation provided that the patient is treated in the first weeks of life. At present, family history is the only way to identify patients that are asymptomatic with most patients being diagnosed after onset of symptoms. We hypothesized that a staging system based on clinical indicators and neurophysiological and neuroimaging measures can predict posttreatment variation in patients diagnosed with infantile Krabbe disease. METHODS. A retrospective review of pretransplant clinical indicators and neurodevelopmental, brain imaging and neurophysiological measures was performed in 42 patients being considered for treatment with umbilical cord blood transplantation. Based on these evaluations, an expert system approach was used to develop a staging system for infantile Krabbe disease. Another set of analyses in the subset of patients who were transplanted (n = 29) evaluated the association between pretransplant stage of disease and posttransplant neurodevelopmental outcomes. RESULTS. A staging algorithm for infants with infantile Krabbe disease was developed and tested for predicting neurodevelopmental outcome after umbilical cord blood transplantation. Standard neurophysiological and neuroimaging tests were not useful in the staging algorithm. Clinical indicators were found to best classify stage of disease. Pretransplant stage was found to be predictive of neurodevelopmental outcome. CONCLUSIONS. We conclude that the clinical staging system based solely on signs and symptoms of disease can be used to predict outcomes after umbilical cord blood transplantation. This staging system can be used prospectively to guide physicians unfamiliar with the disorder in evaluating, monitoring, and counseling families about treatment outcomes. The staging will be useful for both patients diagnosed with infantile Krabbe disease because of clinical symptoms and those identified through neonatal screening programs.