Intellectual Developmental Disorder, X-Linked, Syndromic, Lubs Type, also known as mecp2 duplication syndrome, is related to rett syndrome and encephalopathy, neonatal severe, due to mecp2 mutations, and has symptoms including ataxia, constipation and muscle rigidity. An important gene associated with Intellectual Developmental Disorder, X-Linked, Syndromic, Lubs Type is MECP2 (Methyl-CpG Binding Protein 2). Affiliated tissues include eye and brain, and related phenotypes are ptosis and global developmental delay