title: Neurodevelopmental side effects of bone marrow transplantation: two case illustrations of identical twins.
abstract: OBJECTIVE
  Bone marrow transplantation (BMT), particularly preparative regimens, may have a significant impact on the developing nervous system. However, the effects of various BMT regimens on children's growth and development have been poorly documented to date. Twins serve as ideal subjects to study the impact of medical treatment, since they control for nonmedical (genetic and environmental) influences upon neurodevelopmental outcome.
  
  
  METHODS
  Two cases of monozygotic twins are presented to illustrate the impact of BMT regimens. Growth data and neurocognitive testing are presented for each patient (affected twin) in relation to his/her syngeneic BMT donor and case control (control twin).
  
  
  RESULTS
  These two cases illustrate the growth retardation that has been reported after BMT. However, changes in growth trends across twins appear to have begun after diagnosis, rather than after BMT per se. Comparisons of cognitive test results within these twin pairs illustrate learning problems in the affected twins. However, there was also evidence of learning anomalies in the unaffected twins.
  
  
  CONCLUSIONS
  Results underscore the importance of longitudinal assessment in order to identify the side effects of BMT regimens for children. Differences across the two cases highlight important research questions regarding variables associated with patients, disease, and treatment (e.g., age at the time of BMT, previous neurotoxic treatments, underlying disease) and emphasize the importance of controls in this line of research.
authors.affiliation: Department of Hematology/Oncology, Children's National Medical Center, Washington, D.C., USA.
authors.forename: M A
authors.initials: MA
authors.lastname: McCabe
authors.forename: H
authors.initials: H
authors.lastname: Crowe
authors.forename: R
authors.initials: R
authors.lastname: Quinones
mesh_terms: D016026:Bone Marrow Transplantation / Q000009:adverse effects*; D002658:Developmental Disabilities / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006130:Growth Disorders / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D007223:Infant; D008297:Male; D009447:Neuroblastoma / Q000628:therapy*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000628:therapy*; D014427:Twins