Clinical and neurobiological correlates of cytogenetic abnormalities in childhood-onset schizophrenia

Objective: Cytogenetic abnormalities are increased in schizophrenia, sugges ting a possible etiologic contribution. However, their clinical and pathoph ysiologic roles in the disorder are unknown. To investigate this, a group o f children and adolescents participating in a comprehensive study of childh ood-onset schizophrenia were screened for chromosomal abnormalities, and th eir clinical and neurobiological correlates were examined. Method: Cytogene tic screening with the use of high-resolution banding, fluorescent in situ hybridization for chromosome 22q11 deletions, and molecular fragile X testi ng was undertaken in a group of 47 children and adolescents with very early onset of schizophrenia. Clinical, neurobiological (including brain morphom etry), and risk factor measures of the subjects with cytogenetic abnormalit ies were compared with those of the remaining patients without cytogenetic anomalies. Results: Five patients had previously undiagnosed cytogenetic ab normalities. Lower performance IQ and more pronounced premorbid development al impairments were seen in this subgroup. Rates of obstetric complications , familial schizophrenia spectrum disorders, and familial eye tracking dysf unction were similar for the patients with and without cytogenetic abnormal ities. Conclusions: Cytogenetic abnormalities appear to be increased in chi ldhood-onset schizophrenia, suggesting an association with a very early age at onset. The data from the subgroup of patients with cytogenetic anomalie s are consistent with a model in which a childhood onset of schizophrenia i s due to a greater impairment of neurodevelopment secondary to the interact ion of a number of factors, particularly genetic ones.