MECP2 Mutations in the Rett Syndrome Patients from South India

Background: Rett syndrome (RTT) is a rare neurological disorder that primarily affects the females. Most cases of RTT are caused by a de novo mutation in the MECP2 gene located on the X chromosome. About 1000 MECP2 mutations have been found to be associated with RTT. Objective: The present study is aimed at the mutation screening of MECP2 gene in the RTT patients belonging to the south Indian state of Kerala. Materials and Methods: In total 22 girls with a clinical suspicion of RTT were recruited for the study. Exons 2, 3. and 4 of MECP2 were amplified and sequenced. Results: MECP2 mutations were observed in 12 patients. While 7 mutations were pathogenic, 4 were benign. All of the mutations were located in exons 3 and 4 of MECP2, spanning the methyl-CpG DNA binding domain (MBD), transcription repression domain (TRD), and C-terminal domain (CTD) domains of the MECP2 protein. Four novel mutations were identified. There were no mutations in the MECP2gene of 10 patients with a clinical suspicion of RTT. Conclusions: A recommended screening strategy for RTT is to first look for mutations in exons 3 and 4 of MECP2, followed by exons 1 and 2, testing for large deletions in MECP2, and screening for mutations in genes, such as CDKL5 and FOXG1 that are reported to cause a Rett-like phenotype.