Molecular Testing of MECP2 Gene in Rett Syndrome Phenotypes in Indian Girls

ABSTRACT

Objective: To assess yield of MECP2 gene sequence variationsanalysis and large deletions in suspected cases of Rettsyndrome.Design: Descriptive study.Setting: Tertiary-care medical genetics center.Patients Girls with neuroregression, postnatal microcephaly andsigns and symptoms suggestive of classical and atypical Rettsyndrome were classified into two groups. Group I consisted ofgirls with Classical and atypical Rett syndrome on basis on theRevised Rett Syndrome diagnostic criteria, 2010. Group II includedgirls with neuroregression and postnatal microcephaly and otherRett like features but not fulfilling the above criteria.Procedure Sanger sequencing of coding regions and largedeletional analysis of MECP2 gene.Outcome measure: Identification of mutation in MECP2 gene.Result: Mutation in MECP2 gene was identified in 74% (14/19) ingroup I and none (0/17) in group II. The mutation detection ratewas 93% (13/14) in group I classical Rett syndrome girls (2 withlarge deletions identified with Multiplex ligation dependent probeamplification) and 20% (1/5) in group I atypical Rett syndromegirls. One novel MECP2 sequence variation was identified ingroup I classical Rett syndrome.Conclusion: The yield of the mutation detection in MECP2 ishigher in classical Rett syndrome. In girls with some Rett likefeatures, but not fulfilling revised Rett syndrome diagnosticcriteria, mutation testing for MECP2 gene has a low yield