| Definition: |
A syndromic X-linked intellectual disability that is characterized primarily by severe mental retardation, dysmorphic facies, and a highly skewed X-inactivation pattern in carrier women and that has_material_basis_in mutation in the ATRX gene. X-linked mental retardation-hypotonic facies syndrome comprises several syndromes previously reported separately. These include Carpenter-Waziri, Holmes-Gang, and Smith-Fineman-Myers syndromes. X-linked alpha-thalassemia/mental retardation syndrome is an allelic disorder with a similar phenotype with the addition of alpha-thalassemia and Hb H inclusion bodies in erythrocytes. |