MEF2C Mutations: The Cause of an Epileptic Encephalopathy Syndrome with Pathognomonic Fidgetiness and Myoclonias

Background/Purpose: Deletion syndromes are well ascertainable by array CGH. Causative genes can be delineated in spite of sometimes otherwise unspecific clinical symptoms.

Methods/Results: We report on an infant, who was diagnosed with a 5q14.3 deletion syndrome. Breaking points were localized to two exons of the MEF2C gene. The child initially presented at 4 weeks of age with fidgetiness and hypermotoric arm movements. Rapidly, myoclonic epilepsy and psychomotor retardation became apparent. These symptoms were previously described in association with mutations in the MEF2C gene. Dysmorphic signs are subtle with a mildly protruding forehead, hypertelorism, and relatively slender midfacial structures. Malformations are not associated. The disease pattern can be classified as an epileptic encephalopathy syndrome; valproate is an effective basic therapy.

Conclusion: Stereotypical hyperkinesia in an infant, associated with myoclonic seizures and discrete dysmorphic signs, should prompt evaluation for MEF2C gene mutations.