Craniofacial dysmorphogenesis in fetally irradiated nonhuman primates: implications for the neurodevelopmental hypothesis of schizophrenia

Background Craniofacial abnormalities arising from gestational disturbances have been documented in some schizophrenic patients. Reduction of thalamic neurons, a key feature of the neuropathology of schizophrenia, could also have a prenatal origin via disruption of thalamic neurogenesis. This study investigates whether craniofacial dysmorphology and thalamic neuron loss might be associated manifestations of a disruption in embryonic development. Methods Thalamic neurons were deleted by exposing fetal macaques to x-rays during thalamic genesis (E33–42). Another group of macaques was irradiated after thalamic genesis (E70–81). Body, head, and facial measurements were obtained from the early irradiated (EX), late irradiated (LX), and control animals at adulthood. Results Head width, distance between outer eye edges, and ear width were smaller in EX macaques compared with control animals. The LX macaques exhibited only reduced ear width compared with control animals. Conclusions These findings indicate that certain features of thalamic neuropathology and craniofacial dysmorphogenesis observed in schizophrenic patients may have a common etiology.