Asadollahi-Rauch syndrome (MED13L haploinsufficiency syndrome or MED13L-related intellectual disability) is a rare condition with an estimated prevalence of 1.6 per 100,000 births and is characterized by moderate to severe intellectual disability, low muscle tone (hypotonia), and some especial facial features such as open mouth and big tongue. Speech and language development, and unaided walking is likely delayed in the patients and coordination problems may be present. Some of the patients may have autism, or may develop seizures (epilepsy). Almost half of the patients have some type of growth problems such as abnormal head size or weight. Abnormal findings in brain MRI have been reported in some patients. Some patients are born with structural malformations of the heart which may need surgical correction.
Mutations which cause the disorder are usually leading to reduction of the MED13L protein function. Disease causing mutations in the patients are usually not inherited from healthy parents and usually occur newly (de novo) in sperm or egg.