Authors: Le Thi Thanh Huong 1*, Do Thi Diem Trinh 1*, Vu Duy Chinh 2, Ly Thi Thanh Ha 1, Bui Thi Phuong Hoa 1, and Nguyen Thanh Liem 1.
1 Department of Gene Technology, Vinmec Stem Cell and Gene Technology Research Institute, 458 Minh Khai, Hai Ba Trung District, Hanoi, Vietnam
2 Vinmec International General Hospital, 458 Minh Khai, Hai Ba Trung District, Hanoi, Vietnam
*Contact information: huongev.nihe@gmail.com
Journal: BMC Medical Genetics, Volume 19, Page 137, 2018.
Received: 20 March 2018; Accepted: 30 July 2018.
Online published: 06 August 2018.
DOI: https://doi.org/10.1186/s12881-018-0658-x .
Introduction: Rett syndrome (RTT) is a severe neurodevelopmental disorder in children, characterized by a period of normal neurodevelopment in children from 6 to 18 months, followed by the onset of motor and language impairment combined with stereotyped hand movements. RTT syndrome occurs mainly due to de novo mutations (mutations that arise during fetal development) in the MECP2 (methyl-CpG-binding protein 2) gene.
Method: This study was conducted on 27 female patients with typical RTT syndrome, aged between 18 and 48 months. Specialists performed clinical assessments and made diagnoses based on the RTT diagnostic criteria. Blood samples were collected from the patients for testing and DNA extraction. Subsequently, we amplified the MECP2 gene and sequenced the coding region to identify mutations in this gene.
Results: Mutations in the MECP2 gene were found in 20 patients (74%) including 2 missense mutations, 4 nonsense mutations, 6 frameshift mutations, and 2 deletion mutations. Of the 14 mutations identified in this study, 4 mutations, according to point analysis, were discovered for the first time and have never been published in any databases or reports: c.1384-1385DelGT, c.1205insT, c.717delC, and c.1132_1207del77. The C > T ratio was found to be high (70%) in CpG region mutations.
Conclusion: Our results show a high C > T mutation rate in the CpG region, which is a commonly altered gene region often identified in Rett syndrome patients, a condition primarily caused by arising mutations. This study is the first to identify the mutation spectrum of the MECP2 gene in Vietnamese patients and represents an important step toward improving diagnosis and care for Rett syndrome patients.
