Neuropathologic features in adults with 22q11.2 deletion syndrome.

The 22q11.2 deletion syndrome (22qDS) is the most common microdeletion syndrome in humans. Its multisystem manifestations include congenital anomalies and neuropsychiatric disorders such as schizophrenia. Structural neuroimaging shows various abnormalities, but no postmortem brain studies exist. We report neuropathologic findings in 3 individuals from a cohort of 100 adults with a confirmed 22q11.2 deletion. All 3 had schizophrenia. Postmortem examination of Case 1, a 44-year-old male, revealed bilateral periventricular nodular heterotopia in the frontal lobes and ectopic neurons scattered throughout the frontal white matter. Cases 2 (male, aged 22 years) and 3 (female, 52 years) showed no evidence of migration abnormalities, but both had extensive astrocytic gliosis and focal collections of macrophages in the cerebral white matter, suggestive of cerebrovascular pathology. Review of magnetic resonance imaging findings available for 66 other subjects in the cohort revealed polymicrogyria in one and right cerebellar disorganization in another of the 26 subjects with schizophrenia. The results support previous neuroimaging reports suggesting that neuronal migration abnormalities may be a feature of 22qDS. Both early developmental brain abnormalities and fetal and later microvascular pathology may play a role in the pathogenesis of the neuropsychiatric phenotype of 22qDS, including white matter abnormalities and schizophrenia.