We report on patients with heterozygous defects in CNTNAP2 or NRXN1 associated with severe intellectual disability, which has only been reported for recessive defects before.
Whereas the established synaptic role of NRXN1 suggests that synaptic defects contribute to the associated neuropsychiatric disorders and to severe MR as reported here, evidence for a synaptic role of the CNTNAP2-encoded protein CASPR2 has so far been lacking.