The cerebral cortex was examined for signs of pathology in the NZB, BXSB, and MRL autoimmune strains of mice, crosses among these strains, and control mice. Previously, we reported that 20% of NZB mice had ectopic collections of neurons in layer I of the cortex. In this study we replicated this finding in the NZB, and extended it to the BXSB strain, and BXSB/NZB and MRL/NZB hybrids. The MRL strain, however, did not have a large number of individuals with brain anomalies. Thus, a number of autoimmune mice strains and hybrids develop brain anomalies, although at least one autoimmune strain does not. We suggest that in certain autoimmune strains maternal autoantibodies cross the placenta and damage the developing fetal brain, and that these strains may be useful experimental models for studying the development of brain anomalies seen in the dyslexic human.