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Sharaf-Eldin WE, Soliman HN, Abdel-Aziz NN, Elbendary HM, Issa MY, Zaki MS. Mutation spectrum in the gene encoding methyl-CpG-binding protein 2 in Egyptian patients with Rett syndrome. Meta Gene 2020. [DOI: 10.1016/j.mgene.2019.100620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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First description of an unusual novel double mutation in MECP2 co-occurring with the m.827A>G mutation in the MT-RNR1 gene associated with angelman-like syndrome. Int J Dev Neurosci 2019; 79:37-44. [PMID: 31647993 DOI: 10.1016/j.ijdevneu.2019.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/01/2019] [Accepted: 10/07/2019] [Indexed: 11/20/2022] Open
Abstract
Mutations in Methyl-CpG-Binding protein 2 (MECP2), located on Xq28 and encoding a methyl CpG binding protein, are commonly related to Rett syndrome. However, MECP2 mutations have already been reported in patients with neurodevelopmental abnormalities such as X-linked mental retardation, severe neonatal encephalopathy and Angelman-like syndrome (AS-like). Accordingly, we report the clinical, molecular and bioinformatic analyses in a Tunisian patient with AS-like phenotype. In fact, the direct sequencing of MECP2 and cloning essay reveals the emergence of an unusual novel double mutation, including a de novo mutation c.397C > T (p.R133C) and an inherited one c.608C > T (p.T203 M) co-occurring in Trans. We also provide the molecular evidence of the c.608C > T transmission to the patient which was present in her father at somatic mosaicism state. To gain insight into the molecular basis of this disorder, we undertook, for the first time, a whole mitochondrial genome mutational analysis. Thus, the results showed the presence of several variations and a homoplasmic mutation m.827A > G in the MT-RNR1 gene, leading to the disruption of the 12S rRNA secondary structure. Our report is considered as the first to describe an unusual novel double mutation (c.397C > T in trans with c.608C > T) in MECP2 co-occurring with the mitochondrial m.827A > G mutation in the MT-RNR1 gene in a Tunisian patient with AS-like. Besides, our results highlight the importance of studying MECP2 and the significance of mDNA screening in AS-like disorder for a better understanding of its etiopathogenesis.
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NASIRI J, SALEHI M, HOSSEINZADEH M, ZAMANI M, FATTAHPOUR S, ARYANI O, FAZEL NAJAFABADI E, JABARZADEH M, ASADI S, GHOLAMREZAPOUR T, SEDGHI M, GHORBANI F. Genetic Analysis of MECP2 Gene in Iranian Patients with Rett Syndrome. IRANIAN JOURNAL OF CHILD NEUROLOGY 2019; 13:25-34. [PMID: 31327966 PMCID: PMC6586453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 11/29/2017] [Accepted: 12/19/2017] [Indexed: 11/06/2022]
Abstract
OBJECTIVES Rett syndrome is an X linked dominant neurodevelopmental disorder which almost exclusively affects females. The syndrome is usually caused by mutations in MECP2 gene, which is a nuclear protein that selectively binds CpG dinucleotides in the genome. MATERIALS & METHODS To provide further insights into the distribution of mutations in MECP2 gene, we investigated 24 females with clinical characters of Rett syndrome referred to Alzahra University Hospital in Isfahan, Iran during 2015-2017. We sequenced the entire MECP2 coding region and splice sites for detection of point mutations in this gene. Freely available programs including JALVIEW, SIFT, and PolyPhen were used to find out the damaging effects of unknown mutations. RESULTS Direct sequencing revealed MECP2 mutations in 13 of the 24 patients. We identified in 13 patients, 10 different mutations in MECP2 gene. Three of these mutations have not been reported elsewhere and are most likely pathogenic. CONCLUSION Defects in MECP2 gene play an important role in pathogenesis of Rett syndrome. Mutations in MECP2 gene can be found in the majority of Iranian RTT patients. We failed to identify mutations in MECP2 gene in 46% of our patients. For these patients, further molecular analysis might be necessary.
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Affiliation(s)
- Jafar NASIRI
- Department of Paediatric Neurology, Faculty of Medicine, Child Growth and Development Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mansoor SALEHI
- Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Majid HOSSEINZADEH
- Department of Medical Genetics, School of Medicine, International Campus, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahdi ZAMANI
- Department of Medical Genetics, School of Medicine, International Campus, Tehran University of Medical Sciences, Tehran, Iran
| | - Shirin FATTAHPOUR
- Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Omid ARYANI
- Department of Neuroscience, Iran University of Medical Sciences, Tehran, Iran
| | - Esmat FAZEL NAJAFABADI
- Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Maryam JABARZADEH
- Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Sara ASADI
- Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Tahereh GHOLAMREZAPOUR
- Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Maryam SEDGHI
- Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Fatemeh GHORBANI
- Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
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Kharrat M, Kamoun Y, Kamoun F, Ellouze E, Maalej M, Fendri-Kriaa N, Ammar-Keskes L, Belghith N, Gargouri A, Triki C, Fakhfakh F. Clinical, Molecular, and Computational Analysis in Patients With a Novel Double Mutation and a New Synonymous Variant in MeCP2: Report of the First Missense Mutation Within the AT-hook1 Cluster in Rett Syndrome. J Child Neurol 2017; 32:694-703. [PMID: 28399682 DOI: 10.1177/0883073817701622] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Rett syndrome is an X-linked neurodevelopmental disorder, primarily caused by MECP2 mutations. In this study, clinical, molecular and bioinformatics analyses were performed in Rett patients to understand the relationship between MECP2 mutation type and the clinical severity. Two double MeCP2 mutations were detected: a novel one (p.G185 V in cis with p.R255X) in P1 and a known one (p.P179 S in cis with p.R255X) in P2. Besides, a novel synonymous mutation (c.807C>T; p.G269G), which could affect mRNA splicing, was identified in P3. The results from clinical severity analysis have shown that P1 was more severely affected than P2 with CSS being 35 and 14, respectively. Therefore, the phenotypic variability in P1 and P2 could be explained by the potential pathogenic effect of the RTT-causing missense mutation p.G185 V in the AT-hook1. In conclusion, clinical, molecular, and in silico investigations in the studied patients have been proven to be substantial for the genotype-phenotype correlation.
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Affiliation(s)
- Marwa Kharrat
- 1 Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Sfax, Tunisia.,2 Laboratory of Human Molecular Genetics, Faculty of Medicine, Sfax, Tunisia
| | - Yosra Kamoun
- 3 Laboratory of Molecular Biotechnologie of Eukaryotes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Fatma Kamoun
- 4 Service de Neurologie Infantile, C.H.U. Hédi Chaker de Sfax, Tunisia
| | - Emna Ellouze
- 4 Service de Neurologie Infantile, C.H.U. Hédi Chaker de Sfax, Tunisia
| | - Marwa Maalej
- 2 Laboratory of Human Molecular Genetics, Faculty of Medicine, Sfax, Tunisia
| | - Nourhene Fendri-Kriaa
- 1 Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Sfax, Tunisia
| | - Leila Ammar-Keskes
- 2 Laboratory of Human Molecular Genetics, Faculty of Medicine, Sfax, Tunisia
| | - Neila Belghith
- 2 Laboratory of Human Molecular Genetics, Faculty of Medicine, Sfax, Tunisia
| | - Ali Gargouri
- 3 Laboratory of Molecular Biotechnologie of Eukaryotes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Chahnez Triki
- 4 Service de Neurologie Infantile, C.H.U. Hédi Chaker de Sfax, Tunisia
| | - Faiza Fakhfakh
- 1 Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Sfax, Tunisia
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