Main clinical features
Houge type X-linked intellectual disability (CNKSR2 syndrome) is a rare epilepsy disorder which is associated with developmental delay or intellectual disability.
One of the key features of the condition is impaired or absent speech or loss of acquired language.
Seizures usually begin around the age of 2-3 years and are associated with a highly abnormal EEG appearance during sleep.
The condition is associated with both deletions and point mutations within the CNKSR2 gene.
The condition is rare. The first patients were reported in 2012 by Houge et al., with only three further reports in the subsequent five years. Damiano et al. identified one patient with a CSNKR2 variant within a cohort of 112 patients with epilepsia and aphasia.
The inheritance pattern is X-linked. Most reported patients have been males, but several more mildly affected females have been reported