As stated before, in females, heterozygous X-linked mutations in PCDH19 have been linked to EFMR, while in males, mosaic PCDH19 mutations are responsible for treatment-resistant epilepsy presenting similarly to EFMR, with some reported cases of comorbid intellectual disability, including autism and other behavioral problems [40,41]. The gene discussed is PCDH19; the disease is epilepsy.