The int22h1/int22h2-mediated Xq28 duplication syndrome is an X-linked intellectual disability syndrome characterized by variable degrees of cognitive impairment (typically more severe in males), a wide spectrum of neurobehavioral abnormalities, and variable facial dysmorphic features. Affected males also exhibit a peculiar combination of recurrent sinopulmonary infections and atopy, findings that have not been observed in affected females. All males reported to date with the syndrome have moderate-to-severe intellectual disability; in contrast, a minority of heterozygous females have been reported to have mild intellectual disability, while the majority have no discernible health or learning issues and are considered clinically unaffected. [from GeneReviews]