This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Malignant migrating partial seizures of infancy (MMPSI) is a severe form of epilepsy, a condition characterized by recurrent seizures. In MMPSI, specifically, partial seizures generally begin shortly after birth and are often not responsive to treatment. Although the seizures may occur relatively infrequently in the beginning, within a few months the frequency increases drastically with some affected people experiencing clusters of 5 to 30 seizures several times per day. Signs and symptoms associated with these episodes vary based on which part of the brain is affected during a given seizure. Although the seizures associated with MMPSI do eventually become less frequent, the long-term consequences of the condition may include profound developmental delay, microcephaly (unusually small head size), intellectual disability and a shortened lifespan (many do not survive past infancy or early childhood). Although the underlying cause of MMPSI is not fully understood, de novo mutations in certain genes have been identified in several affected people and are thought to be involved in the development of the condition. Even when a genetic cause is identified, most cases of MMPSI occur sporadically in people with no family history of the condition. Treatment is generally focused on minimizing recurrent seizures. Unfortunately, the seizures associated with MMPSI are usually not well-controlled with medications that are typically prescribed to treat epilepsy.
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