Three Intellectual Disability-associated De novo Mutations in MECP2

We applied trio-based whole-exome sequencing and in silico analysis for genetic diagnosis of 294 children with intellectual disability. Three de novo heterozygous mutations [NM_004992.3: c.502C>T, p.(Arg168*), c.916C>T, p.(Arg306Cys), and c.879C>G, p.(Ile293Met)] in MECP2 were identified in three unrelated girls. The first two mutations (c.502C>T, rs61748421; c.916C>T, rs28935468) were detected in two patients who were diagnosed as typical Rett syndrome, X-linked ID and psychomotor retardation. The third mutation (c.879C>G, rs587783140), an extremely rare and previously unreported, was found in a 6-year-old girl with ID, microcephaly, and psychomotor retardation.