AFF2 and Intellectual disability: The literature review showed that variants affecting the AFF2 gene are mainly associated with the Intellectual Developmental Disorder X-Linked 109 (FRAXE, OMIM, #309548), a rare type of intellectual disability without well-characterized specific phenotypic abnormalities (Flynn et al., 1993; Mulley et al., 1995; Gecz et al., 1996).