Rett Syndrome without MECP2 Mutation in a Pakistani Girl

Rett syndrome is a rare inherited neurodegenerative disease which mostly affects females but has a lethal impact on males. Rett syndrome is mostly caused by mutations of Methyl CpG binding protein-2 (MECP2) gene located on chromosome Xq28. A 7-year girl from a consanguineous Pakistani family presented with history of abnormal social behavior, tonic colonic seizures, limb's ataxia, intellectual disability, growth retardation and speech abnormalities. Physical and neurological examinations established likely clinical features of Rett syndrome with abnormal electroencephalogram (EEG). Genetic testing of MECP2 gene did not identify any functional nucleotide variation indicating the involvement of another gene mutation in this patient. A consanguineous case of Rett syndrome did not carry the mutation of MECP2 gene. Due to heterogeneity of the phenotype, it is proposed that there might be involvement of another locus for this disease. In future, targeted next generation sequence can be helpful to identify the causative mutation in this patient.