Neurodevelopmental outcomes following hematopoietic cell transplantation for patients with severe combined...

Hematopoietic cell transplantation (HCT) is a potentially curative treatment for severe combined immunodeficiency (SCID). Since the initiation of newborn screening (NBS), survival rates have improved significantly, but the impact of HCT upon neurodevelopment for patients with SCID requires more investigation. We performed a cross-sectional study of subjects with SCID in North America to assess the impact of NBS, transplant conditioning regimen, and genotype on neurodevelopmental outcomes after HCT. 69 subjects with SCID from 17 PIDTC centers (excluding those with ADA deficiency), ages 6-16 years, received comprehensive standardized neurodevelopmental testing of cognitive, behavioral, and emotional function. Compared with the normative population, our subjects performed in the average range. We found no impact of NBS, chemotherapy conditioning, or genotype. Multivariate analysis revealed a significant decrease in IQ in subjects whose families earned <$50,000 per year. We recommend that children treated by HCT for SCID be monitored with periodic cognitive and behavioral assessments for deficits that could potentially impact long-term ND outcomes.