MED13L haploinsufficiency syndrome is a genetic syndrome that causes intellectual disability, speech problems, and behavioral problems. People with the syndrome usually have distinctive facial features, such as eyes that slant upwards, a flat nasal bridge with a bulb-like tip, very small chin (micrognathia), large and low-set ears, and broad forehead. Most children with the syndrome have poor muscle tone (hypotonia) and may take longer to learn to sit and walk independently (delayed motor skills). Some babies with MED13L haploinsufficiency syndrome are born with heart defects, which may be mild or severe. Other features may include short stature, cleft palate, problems with coordination (ataxia), and recurrent seizures (epilepsy).