This report describes general characteristics of the group of diseases classified as intellectual disability, X-linked, syndromic, also described as mental retardation, X-linked syndromic. This is a genetically heterogeneous set of disorders with many causative genes and mapped loci; the prefix 'MRX' is frequently used in naming X-linked implicated genes for both syndromic and nonsyndromic forms. A comprehensive list of X-linked syndromic subtypes, as defined by OMIM (which number 50 to date), may be found by following the link in the "OMIM phenotypic series" section, below. A subset of these may be found in the table below, with links to more detailed reports for subtypes that have been investigated using fly models.
[updated Mar. 2020 by FlyBase; FBrf0222196]
Intellectual disability is characterized by impairments in intellectual functioning and adaptive behavior; symptoms must be present before a child becomes 18 years old (http://medical-dictionary.thefreedictionary.com/mental+retardation; 2016.01.19).
Intellectual disability can be subdivided into syndromic forms, characterized by cognitive impairment accompanied by dysmorphic features, malformations or neurological abnormalities, and nonsyndromic forms, characterized by cognitive impairment without additional features (Basel-Vanagaite, 2008; DOI: 10.1002/9780470015902.a0021454).