Rasmussen's encephalitis is a progressive childhood disease of unknown cause characterized by severe epilepsy, hemiplegia, dementia, and inflammation of the brain. During efforts to raise antibodies to recombinant glutamate receptors (GluRs), behaviors typical of seizures and histopathologic features mimicking Rasmussen's encephalitis were found in two rabbits immunized with GluR3 protein. A correlation was found between the presence of Rasmussen's encephalitis and serum antibodies to GluR3 detected by protein immunoblot analysis and by immunoreactivity to transfected cells expressing GluR3. Repeated plasma exchanges in one seriously ill child transiently reduced serum titers of GluR3 antibodies, decreased seizure frequency, and improved neurologic function. Thus, GluR3 is an autoantigen in Rasmussen's encephalitis, and an autoimmune process may underlie this disease.

Epilepsy and Mental Retardation limited to Females (EFMR) which links to Xq22 has been reported in only one family. We aimed to determine if there was a distinctive phenotype that would enhance recognition of this disorder. We ascertained four unrelated families (two Australian, two Israeli) where seizures in females were transmitted through carrier males. Detailed clinical assessment was performed on 58 individuals, using a validated seizure questionnaire, neurological examination and review of EEG and imaging studies. Gene localization was examined using Xq22 microsatellite markers. Twenty-seven affected females had a mean seizure onset of 14 months (range 6-36) typically presenting with convulsions. All had convulsive attacks at some stage, associated with fever in 17 out of 27 (63%). Multiple seizure types occurred including tonic-clonic (26), tonic (4), partial (11), absence (5), atonic (3) and myoclonic (4). Seizures ceased at mean 12 years. Developmental progress varied from normal (7), to always delayed (4) to normal followed by regression (12). Intellect ranged from normal to severe intellectual disability (ID), with 67% of females having ID or being of borderline intellect. Autistic (6), obsessive (9) and aggressive (7) features were prominent. EEGs showed generalized and focal epileptiform abnormalities. Five obligate male carriers had obsessional tendencies. Linkage to Xq22 was confirmed (maximum lod 3.5 at = 0). We conclude that EFMR is a distinctive, under-recognized familial syndrome where girls present with convulsions in infancy, often associated with intellectual impairment and autistic features. The unique inheritance pattern with transmission by males is perplexing. Clinical recognition is straightforward in multiplex families due to the unique inheritance pattern; however, this disorder should be considered in smaller families where females alone have seizures beginning in infancy, particularly in the setting of developmental delay. In single cases, diagnosis will depend on identification of the molecular basis.