Opitz-Kavaggia syndrome

Opitz-Kavaggia syndrome

An X-linked recessive mental retardation syndrome (OMIM:305450) characterised by dysmorphic features, including relative macrocephaly, hypertelorism, downslanted palpebral fissures, prominent forehead with frontal hair upsweep, and broad thumbs and halluces; accompanied by hypotonia, constipation and partial agenesis of the corpus callosum; variably accompanied by sensorineural hearing loss and joint laxity evolving into joint contractures. 
Molecular pathology
Caused by defects of MED12, which encodes a protein of the CDK8 subcomplex that modulates mediator complex-polymerase II interactions, thereby regulating transcription initiation and re-initiation rates.