Non-Syndromic X-Linked Intellectual Disability 99, also known as x-linked mental retardation 99, is related to female-restricted syndromic x-linked intellectual disability 99 and intellectual developmental disorder, x-linked 99. An important gene associated with Non-Syndromic X-Linked Intellectual Disability 99 is USP9X (Ubiquitin Specific Peptidase 9 X-Linked), and among its related pathways/superpathways are Deubiquitination and Protein ubiquitination.