Pathogenic variants in the X-linked KIAA2022 gene are known to cause severe intellectual disability in males. Until now, all reported related female carriers of these KIAA2022 disruptions were unaffected and only 3 affected female patients have been described so far. We now report 14 female patients with heterozygous de novo loss of function mutations of KIAA2022. Twelve patients had epilepsy and 13 had mild to severe intellectual disability. This article provides an extensive clinical description of the affected females, providing clinicians with useful information for genetic counseling. Our data strongly suggest that pathogenic KIAA2022 variants can lead to a phenotype not only in males, but also in females. (By Iris de Lange, http://jmg.bmj.com/content/early/2016/06/29/jmedgenet-2016-103909 )