MEF2C haploinsufficiency syndrome is an emerging neurodevelopmental disorder associated with intellectual disability, autistic features, epilepsy, and abnormal movements.
To date, one single duplication including MEF2C has been reported in a patient with intellectual disability but its clinical significance remains uncertain also because of the large size of the imbalance.
Recently, haploinsufficiency of MEF2C, located 1.33 Mb distal to RASA1 on chromosome 5q14.3, has been implicated as the genetic etiology underlying a complex array of deficits including mental retardation, hypotonia, absent speech, seizures, and brain anomalies.