Clinical and genetic analysis of two rare male patients with Rett syndrome / 中华医学遗传学杂志

OBJECTIVE@#To conduct clinical and genetic analysis of two male patients with atypical Rett syndrome.@*METHODS@#Collection of clinical data in the two patients and these parents; whole exome sequencing (WES) was used to detect the potential variants, which were verified by Sanger sequencing. X chromosome inactivation (XCI) detection is performed in the Patient 1's mother to detect the allelic expression difference of the MECP2 gene.@*RESULTS@#Patient 1, a 5-year and 10-month-old boy, had mental disorders and mild intellectual disability (ID) (IQ: 54), whose mother had ID. Patient 2 was a 9-month and 18-day-old male presented with recurrent infections, respiratory insufficiency, hypotonia and global developmental delay. WES indentified a hemizygous mutation, c.499C>T (p.R167W), in the MECP2 gene in patient 1, which was inherited from his mother. The inactivation of X chromosome is skewed, and the expression ratio of wild-type and mutant MECP2 is 100%:0. Patient 2 was found a de novo splicing mutation, c.62+2_62+3del in the MECP2 gene. They were both reported pathogenic variant related to Rett syndrome. c.499C>T (p.R167W) was defined as likely pathogenic (PS1+PM2+PP3) and c.62+2_62+3del was pathogenic (PVS1+PM2+PM6) based on American College of Medical Genetics and Genomics standards and guidelines.@*CONCLUSION@#Both the two patients were diagnosed with rare male Rett syndrome, which had atypical clinical manifestations and large difference. Above foundings have revealed novel phenotypes in Chinese male patients with Rett syndrome.

Loss of O-GlcNAcylation on MeCP2 at Threonine 203 Leads to Neurodevelopmental Disorders / 神经科学通报·英文版

Mutations of the X-linked methyl-CpG-binding protein 2 (MECP2) gene in humans are responsible for most cases of Rett syndrome (RTT), an X-linked progressive neurological disorder. While genome-wide screens in clinical trials have revealed several putative RTT-associated mutations in MECP2, their causal relevance regarding the functional regulation of MeCP2 at the etiologic sites at the protein level requires more evidence. In this study, we demonstrated that MeCP2 was dynamically modified by O-linked-β-N-acetylglucosamine (O-GlcNAc) at threonine 203 (T203), an etiologic site in RTT patients. Disruption of the O-GlcNAcylation of MeCP2 specifically at T203 impaired dendrite development and spine maturation in cultured hippocampal neurons, and disrupted neuronal migration, dendritic spine morphogenesis, and caused dysfunction of synaptic transmission in the developing and juvenile mouse cerebral cortex. Mechanistically, genetic disruption of O-GlcNAcylation at T203 on MeCP2 decreased the neuronal activity-induced induction of Bdnf transcription. Our study highlights the critical role of MeCP2 T203 O-GlcNAcylation in neural development and synaptic transmission potentially via brain-derived neurotrophic factor.

Clinical phenotype and genetic analysis of MECP2 duplication syndrome / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical symptom and parental origin of patients with MECP2 duplication syndrome in order to provide a basis for genetic counseling and prenatal diagnosis.@*METHODS@#Clinical symptoms of four patients who were diagnosed with MECP2 duplication syndrome by copy number variation sequencing (CNV-Seq) were reviewed. The maternal origin of the duplications were verified.@*RESULTS@#All patients were males, and CNV-Seq revealed that they have all harbored a duplication in the Xq28 region spanning 0.32 ~ 0.86 Mb, which were derived from asymptomatic mothers. The clinical symptoms of three patients with three copies included delayed speech, intellectual disability, and muscular hypotonia, while the patient with four copies had died at 6 months after birth, with clinical symptoms including recurrent infections, seizures, and spasticity.@*CONCLUSION@#The four cases of MECP2 duplication syndrome have shown complete penetrance and have all derived from asymptomatic mothers. As a stable and reliable method, CNV-Seq can accurately detect the MECP2 duplication syndrome.

Rett syndrome: the Brazilian contribution to the gene discovery / Síndrome de Rett: a contribuição brasileira para a descoberta do gene

ABSTRACT A brief history of the syndrome discovered by Andreas Rett is reported in this paper. Although having been described in 1966, the syndrome was only recognized by the international community after a report by Hagberg et al. in 1983. Soon, its importance was evident as a relatively frequent cause of severe encephalopathy among girls. From the beginning it was difficult to explain the absence of male patients and the almost total predominance of sporadic cases (99%), with very few familial cases. For these reasons, it was particularly difficult to investigate this condition until 1997, when a particular Brazilian family greatly helped in the final discovery of the gene, and in the clarification of its genetic mechanism. Brief references are made to the importance of the MECP2 gene, 18 years later, as well as to its role in synaptogenesis and future prospects.

RESUMO Uma breve história de uma síndrome neurológica descoberta por Andreas Rett é relatada neste artigo. Embora tenha ocorrido em 1966, a síndrome só foi reconhecida pela comunidade internacional após um relato de Hagberget al, em 1983. Logo, sua importância ficou evidente como causa relativamente frequente de encefalopatia grave entre as crianças do sexo feminino. Desde o início, foi difícil explicar a ausência de envolvimento de pacientes do sexo masculino e a quase absoluta preponderância de casos esporádicos (99%), com muitos poucos casos familiares. Por essas razões, foi difícil investigar essa condição até 1997, quando uma família brasileira em particular ajudou muito na descoberta final do gene e no esclarecimento de seu mecanismo genético. São feitas referências sucintas à importância do gene MECP2, dezoito anos depois, bem como ao seu papel na sinaptogênese e nas perspectivas futuras.

Síndrome de Rett: Análisis molecular del gen MECP2 en pacientes chilenas / Rett syndrome: MECP2 gene molecular analysis in Chilean patients

INTRODUCCIÓN: El síndrome de Rett (RTT) es un trastorno neurológico progresivo caracterizado por producir una regresión del desarrollo psicomotor en niñas previamente sanas. La mayoría de los casos son causados por variantes patogénicas en el gen MECP2, que codifica para la proteína methyl CpG- binding protein 2. OBJETIVO: Describir la frecuencia y el tipo de variantes patogénicas en MECP2 en mujeres chilenas con diagnóstico clínico de RTT. PACIENTES Y MÉTODO: Se invitó a participar en este estudio a mujeres chilenas con sospecha clínica de RTT. Se reunió información clínica mediante un cuestionario. Se analizaron variantes patogénicas en MECP2 mediante el método de secuenciación de Sanger y se utilizó Multiple Ligation-dependant Probe Amplification (MLPA) para la detección de duplicaciones y deleciones. RESULTADO: El estudio incluyó 14 pacientes con sospecha de RTT, de las cuales 8 (57%) pacientes tuvieron variantes patogénicas. Las restantes permanecen sin diagnóstico molecular. CONCLUSIÓN: Variantes patogénicas en MECP2 están presentes en pacientes chilenas con RTT. Es probable que haya otros genes o diagnósticos involucrados en las pacientes sin hallazgos en MECP2. A partir de este trabajo, el diagnóstico molecular está disponible en Chile.

INTRODUCTION: Rett syndrome (RTT) is a progressive neurological disorder characterized by regres sion of psychomotor development in previously healthy girls. Most cases are due to pathogenic va riants in the MECP2 gene which encodes for the methyl CpG-binding protein 2. OBJECTIVE: To des cribe the frequency and type of pathogenic variants in the MECP2 gene in Chilean female patients with clinical diagnosis of RTT. PATIENTS AND METHOD: Chilean women with clinical suspicion of RTT were invited to participate in the study. Clinical data were collected through a questionnaire. MECP2 pathogenic variants were analyzed by Sanger sequencing method and Multiplex Ligation-dependent Probe Amplification (MLPA) was used to detect duplications or deletions. RESULTS: The study in cluded 14 patients with suspected RTT, of which eight (57%) patients had pathogenic variants. The other patients remain without molecular diagnosis. CONCLUSIONS: Pathogenic variants in MECP2 are present in Chilean patients with RTT. It is likely that there are other genes or diagnoses involved in patients without MECP2 findings. As of this study, molecular diagnosis is available in Chile.

Molecular diagnosis and functional study of a pedigree affected with Lubs X-linked mental retardation syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a pedigree affected with X-linked mental retardation.@*METHODS@#The proband was subjected to chromosomal karyotyping, FMR1 mutation testing and copy number variation analysis with a single nucleotide polymorphism microarray (SNP array). His family members were subjected to multiplex ligation-dependent probe amplification (MLPA) assaying. Expression of genes within the repeated region were analyzed.@*RESULTS@#The proband had a normal chromosomal karyotype and normal number of CGG repeats within the FMR1 gene. SNP array identified a 370 kb duplication in Xq28 (ChrX: 153 027 633-153 398 515), which encompassed 14 genes including MECP2. The patient was diagnosed as Lubs X-linked mental retardation syndrome (MRXSL). MLPA confirmed the presence of copy number variation, its co-segregation with the disease, in addition with the carrier status of females. Genes from the duplicated region showed higher levels of expression (1.79 to 5.38 folds) within peripheral blood nucleated cells of the proband.@*CONCLUSION@#The patients were diagnosed with MRXSL. The expression of affected genes was up-regulated due to the duplication. Genetic counseling and prenatal diagnosis may be provided based on the results.

Puerarin Up-regulates Methyl-CpG Binding Protein 2 Phosphorylation in Hippocampus of Vascular Dementia Rats / 中国结合医学杂志

<p><b>OBJECTIVE</b>To observe the effect of puerarin on methyl-CpG binding protein 2 (MeCP2) phosphorylation (pMeCP2) in the hippocampus of a rat model of vascular dementia (VD).</p><p><b>METHODS</b>Thirty-six healthy Sprague-Dawley rats were randomly assigned to the sham-operated group, dementia group and puerarintreated group using a random number table (n=12 per group). The modifified permanent bilateral common carotid artery occlusion method was used to establish the VD model. The sham-operated and dementia groups were given 2 mL/d of saline, while the puerarin-treated group was given 100 mg/(kg•d) of puerarin for 17 days. The learning and memory abilities were evaluated by the Morris water maze test. Hematoxylin-eosin staining, immunohistochemical (IHC) staining and Western blot analysis were carried out to observe changes in neuron morphology and in level of pMeCP2 in the hippocampus, respectively.</p><p><b>RESULTS</b>The morphologies of rat hippocampal neurons in the puerarintreated group were markedly improved compared with the dementia group. The escape latency of the dementia group was significantly longer than the sham-operated group (P<0.05), while the puerarin-treated group was obviously shorter than the dementia group (P<0.05). Cross-platform times of the dementia group were signifificantly decreased compared with the sham-operated group (P<0.05), while the puerarin-treated group was obviously increased compared with the dementia group (P<0.05). IHC staining showed no significant difference in the number of MeCP2 positive cells among 3 groups (P>0.05). The number of pMeCP2 positive cells in the CA1 region of hippocampus in the dementia group was signifificantly increased compared with the sham-operated group, and the puerarin-treated group was signifificantly increased compared with the dementia group (both P<0.05). Western blot analysis showed no signifificant difference of MeCP2 expression among 3 groups (P>0.05). The expression of pMeCP2 in the dementia group was signifificantly increased compared with the sham-operated group, while it in the puerarin-treated group was signifificantly increased compared with the dementia group (P<0.05).</p><p><b>CONCLUSION</b>Puerarin could play a role in the protection of nerve cells through up-regulating pMeCP2 in the hippocampus, improving neuron morphologies, and enhancing learning and memory ablities in a rat model of VD.</p>

Dual mechanisms for the regulation of brain-derived neurotrophic factor by valproic acid in neural progenitor cells

Autism spectrum disorders (ASDs) are neurodevelopmental disorders that share behavioral features, the results of numerous studies have suggested that the underlying causes of ASDs are multifactorial. Behavioral and/or neurobiological analyses of ASDs have been performed extensively using a valid model of prenatal exposure to valproic acid (VPA). Abnormal synapse formation resulting from altered neurite outgrowth in neural progenitor cells (NPCs) during embryonic brain development has been observed in both the VPA model and ASD subjects. Although several mechanisms have been suggested, the actual mechanism underlying enhanced neurite outgrowth remains unclear. In this study, we found that VPA enhanced the expression of brain-derived neurotrophic factor (BDNF), particularly mature BDNF (mBDNF), through dual mechanisms. VPA increased the mRNA and protein expression of BDNF by suppressing the nuclear expression of methyl-CpG-binding protein 2 (MeCP2), which is a transcriptional repressor of BDNF. In addition, VPA promoted the expression and activity of the tissue plasminogen activator (tPA), which induces BDNF maturation through proteolytic cleavage. Trichostatin A and sodium butyrate also enhanced tPA activity, but tPA activity was not induced by valpromide, which is a VPA analog that does not induce histone acetylation, indicating that histone acetylation activity was required for tPA regulation. VPA-mediated regulation of BDNF, MeCP2, and tPA was not observed in astrocytes or neurons. Therefore, these results suggested that VPA-induced mBDNF upregulation was associated with the dysregulation of MeCP2 and tPA in developing cortical NPCs.

MECP2 duplication syndrome: a clinical analysis of three cases and literature review / 中国当代儿科杂志

MECP2 duplication syndrome (MDS) is a rare pediatric disease and mainly manifests as delayed motor development, language loss or delay, recurrent infection, severe intellectual disability, epilepsy, autistic symptoms, and early infantile hypotonia. In this article, the three children with this disease were all boys. Cases 1 and 2 had delayed motor development, and language loss or delay as initial manifestations, and case 3 had recurrent infection as initial manifestation. Physical examination showed hypotonia and negative pathological signs in each case. Case 1 had tonic-clonic seizures and electroencephalography showed focal seizures, for which he was given oxcarbazepine, levetiracetam, and clonazepam as the antiepileptic treatment to control seizures. Case 3 experienced one absence seizure and three head-nodding seizures with normal electroencephalographic findings during these seizures, and therefore, he was not given antiepileptic treatment. In each case, recurrent infection was improved with the increase in age, but there were no significant improvements in language or intelligence. Array-based comparative genomic hybridization (aCGH) showed MECP2 duplication in X chromosome in each case, and so they were diagnosed with MDS. MDS should be considered for children with delayed development complicated by recurrent infection and epileptic seizures, and early aCGH helps with the diagnosis of this disease.

MiR-130a regulates neurite outgrowth and dendritic spine density by targeting MeCP2

MicroRNAs (miRNAs) are critical for both development and function of the central nervous system. Significant evidence suggests that abnormal expression of miRNAs is associated with neurodevelopmental disorders. MeCP2 protein is an epigenetic regulator repressing or activating gene transcription by binding to methylated DNA. Both loss-of-function and gain-of-function mutations in the MECP2 gene lead to neurodevelopmental disorders such as Rett syndrome, autism and MECP2 duplication syndrome. In this study, we demonstrate that miR-130a inhibits neurite outgrowth and reduces dendritic spine density as well as dendritic complexity. Bioinformatics analyses, cell cultures and biochemical experiments indicate that miR-130a targets MECP2 and down-regulates MeCP2 protein expression. Furthermore, expression of the wild-type MeCP2, but not a loss-of-function mutant, rescues the miR-130a-induced phenotype. Our study uncovers the MECP2 gene as a previous unknown target for miR-130a, supporting that miR-130a may play a role in neurodevelopment by regulating MeCP2. Together with data from other groups, our work suggests that a feedback regulatory mechanism involving both miR-130a and MeCP2 may serve to ensure their appropriate expression and function in neural development.

The Modulation of Neurotrophin and Epigenetic Regulators: Implication for Astrocyte Proliferation and Neuronal Cell Apoptosis After Spinal Cord Injury

OBJECTIVE: To investigate alterations in the expression of the main regulators of neuronal survival and death related to astrocytes and neuronal cells in the brain in a mouse model of spinal cord injury (SCI). METHODS: Eight-week-old male imprinting control region mice (n=36; 30–35 g) were used in this study and randomly assigned to two groups: the naïve control group (n=18) and SCI group (n=18). The mice in both groups were randomly allocated to the following three time points: 3 days, 1 week, and 2 weeks (n=6 each). The expression levels of regulators such as brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), histone deacetylase 1 (HDAC1), and methyl-CpG-binding protein 2 (MeCP 2) in the brain were evaluated following thoracic contusive SCI. In addition, the number of neuronal cells in the motor cortex (M1 and M2 areas) and the number of astrocytes in the hippocampus were determined by immunohistochemistry. RESULTS: BDNF expression was significantly elevated at 2 weeks after injury (p=0.024). The GDNF level was significantly elevated at 3 days (p=0.042). The expression of HDAC1 was significantly elevated at 1 week (p=0.026). Following SCI, compared with the control the number of NeuN-positive cells in the M1 and M2 areas gradually and consistently decreased at 2 weeks after injury. In contrast, the number of astrocytes was significantly increased at 1 week (p=0.029). CONCLUSION: These results demonstrate that the upregulation of BDNF, GDNF and HDAC1 might play on important role in brain reorganization after SCI.

Functional Profiling of Human MeCP2 by Automated Data Comparison Analysis and Computerized Expression Pathway Modeling / 대한의료정보학회지

OBJECTIVES: Methyl-CpG binding protein 2 (MeCP2) is a ubiquitous epigenetic factor that represses gene expression by modifying chromatin. Mutations in the MeCP2 gene cause Rett syndrome, a progressive neurodevelopmental disorder. Recent studies also have shown that MeCP2 plays a role in carcinogenesis. Specifically, functional ablation of MeCP2 suppresses cell growth and leads to the proliferation of cancer cells. However, MeCP2's function in adult tissues remains poorly understood. We utilized a weight matrix-based comparison software to identify transcription factor binding site (TFBS) of MeCP2-regulated genes, which were recognized by cDNA microarray analysis. METHODS: MeCP2 expression was silenced using annealed siRNA in HEK293 cells, and then a cDNA microarray analysis was performed. Functional analysis was carried out, and transcriptional levels in target genes regulated by MeCP2 were investigated. TFBS analysis was done within genes selected by the cDNA microarray analysis, using a weight matrix-based program and the TRANSFAC 6.0 database. RESULTS: Among the differentially expressed genes with a change in expression greater than two-fold, 189 genes were up-regulated and 91 genes were down-regulated. Genes related to apoptosis and cell proliferation (JUN, FOSL2, CYR61, SKIL, ATF3, BMABI, BMPR2, RERE, and FALZ) were highly up-regulated. Genes with anti-apoptotic and anti-proliferative functions (HNRPA0, HIS1, and FOXC1) were down-regulated. Using TFBS analysis within putative promoters of novel candidate target genes of MeCP2, disease-related transcription factors were identified. CONCLUSIONS: The present results provide insights into the new target genes regulated by MeCP2 under epigenetic control. This information will be valuable for further studies aimed at clarifying the pathogenesis of Rett syndrome and neoplastic diseases.

Functional Profiling of Human MeCP2 by Automated Data Comparison Analysis and Computerized Expression Pathway Modeling / 대한의료정보학회지

OBJECTIVES: Methyl-CpG binding protein 2 (MeCP2) is a ubiquitous epigenetic factor that represses gene expression by modifying chromatin. Mutations in the MeCP2 gene cause Rett syndrome, a progressive neurodevelopmental disorder. Recent studies also have shown that MeCP2 plays a role in carcinogenesis. Specifically, functional ablation of MeCP2 suppresses cell growth and leads to the proliferation of cancer cells. However, MeCP2's function in adult tissues remains poorly understood. We utilized a weight matrix-based comparison software to identify transcription factor binding site (TFBS) of MeCP2-regulated genes, which were recognized by cDNA microarray analysis. METHODS: MeCP2 expression was silenced using annealed siRNA in HEK293 cells, and then a cDNA microarray analysis was performed. Functional analysis was carried out, and transcriptional levels in target genes regulated by MeCP2 were investigated. TFBS analysis was done within genes selected by the cDNA microarray analysis, using a weight matrix-based program and the TRANSFAC 6.0 database. RESULTS: Among the differentially expressed genes with a change in expression greater than two-fold, 189 genes were up-regulated and 91 genes were down-regulated. Genes related to apoptosis and cell proliferation (JUN, FOSL2, CYR61, SKIL, ATF3, BMABI, BMPR2, RERE, and FALZ) were highly up-regulated. Genes with anti-apoptotic and anti-proliferative functions (HNRPA0, HIS1, and FOXC1) were down-regulated. Using TFBS analysis within putative promoters of novel candidate target genes of MeCP2, disease-related transcription factors were identified. CONCLUSIONS: The present results provide insights into the new target genes regulated by MeCP2 under epigenetic control. This information will be valuable for further studies aimed at clarifying the pathogenesis of Rett syndrome and neoplastic diseases.

Bases moleculares del síndrome de Rett, una mirada actual / Molecular basis of Rett syndrome: A current look

El síndrome de Rett (SR) es un trastorno del neurodesarrollo que afecta casi exclusivamente a niñas y cursa secundariamente con autismo. Es poco frecuente y consta de 5 formas clínicas, una clásica y el resto atípicas que comprometen de manera general la habilidad manual, el lenguaje y la motricidad amplia unida a la aparición de estereotipias y epilepsia precoz. Con el objetivo de actualizar la información sobre SR, se aplicaron los descriptores de búsqueda Síndrome de Rett, genes y «Síndrome de Rett¼, «Rett Syndrome gene¼, «Rett Syndrome¼, «Rett Syndrome gene therapy¼ y «Rett Syndrome review¼. Se investigó en los archivos digitales PubMed, Hinari, SCIELO y Medline, y se consultaron los sitios web OMIM, ORPHANET, GeneMap, Genetests, Proteins y Gene, entre otros. Entre 1.348 artículos se seleccionaron 42, los cuales reportan 3 genes causantes del síndrome: MECP2, CDKL5 y FOXG. El gen MECP2 está mutado en el 80% de los pacientes con SR clásico así como en el 40% de los afectados con alguna de sus formas atípicas. El SR con epilepsia precoz y la variante congénita se deben fundamentalmente a variaciones en los genes CDKL5 y FOXG1 respectivamente. Conclusiones: El diagnóstico del SR se basa en criterios clínicos, sin embargo, los avances en la biología molecular y en la genética en particular han abierto el abanico de posibilidades diagnósticas a las diferentes formas clínicas que antes quedaban sin clasificar, a la vez que el análisis molecular permite confirmar el criterio clínico y aportar información en cuanto al pronóstico del paciente.

Rett syndrome (RS) is a neurodevelopmental disorder that exclusively affects girls, and occurs along with autism. It is very uncommon, and has five distinct forms, one classic and the others atypical, which generally compromise manual skills, language, and mobility, and widely associated with the appearance of stereotypy and early epilepsy. With the aim of updating the information about RS, a search was performed in the computer data bases of PubMed, Hinari, SCIELO and Medline, as well as consulting other web sites including OMIM, ORPHANET, GeneMap, Genetests, Proteins and Gene, using the descriptors "Síndrome de Rett", "genes y Síndrome de Rett", "Rett Syndrome gene", "Rett Syndrome", "Rett Syndrome gene therapy", and "Rett Syndrome review". Of the 1,348 articles found, 42 articles were selected, which reported 3 genes causing the syndrome: MECP2, CDKL5 and FOXG. The MECP2 gene is mutated in 80% of patients with classic RS, as well as in 40% of those affected by any of its atypical forms. RS with early epilepsy and the congenital variant are mainly due to variations in the CDKL5 and FOXG1 genes, respectively. Conclusions: The diagnosis of RS is based on clinical criteria. However, the advances in molecular biology and genetics have opened a wide range of possibilities for diagnosing the different clinical forms that could not be classified before. Molecular analysis can help confirm the clinical criteria and provided information as regards the prognosis of the patient.

Advance in research on MECP2 corrected duplication syndrome / 中华医学遗传学杂志

Methyl-CpG-binding protein 2 gene (MECP2; OMIM 300005) is located at chromosome Xq28. Mutations of the gene including point mutation, duplication and deletion can lead to severe neurodevelopmental disorders. The disease caused by duplication of the entire MECP2 gene, named as MECP2 duplication syndrome, is mostly seen in males. The clinical manifestation of this syndrome include mental retardation, hypotonia, poor speech development, recurrent infection, progressive spasticity, epilepsy, autism or autistic features with or without midface hypoplasia. Most patients have inherited the duplication from their unaffected mothers, with only a few cases having de novo mutation. Females with duplicated MECP2 gene are typically asymptomatic because of a skewed X chromosome inactivation (XCI) pattern. Proposed mechanisms of this genomic rearrangement include fork stalling and template switching (FoSTeS) and microhomology mediated break-induced replication (MMBIR). Since no effective treatment is available for this disease, proper genetic counseling and prenatal diagnosis for the high risk families are crucial.

Clinical features and MECP2 mutations in children with Rett syndrome / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the clinical features and mutations in methyl-CpG-binding protein 2 (MECP2) gene among children with classical Rett syndrome in China.</p><p><b>METHODS</b>PCR and direct sequencing were employed to analyze the three exons of MECP2 gene in 9 children recently diagnosed with Rett syndrome and their parents.</p><p><b>RESULTS</b>Heterozygous mutations were identified in 5 out of 9 patients, with a mutation rate of over 50%; there was one case of insert mutation (c.913insT) and 4 cases of missense mutation (exon 3: c.316C>T (R106W); exon 4: c.502C>T (R168X), c.808C>T (R270X), and c.1126C>T (P376S). A new mutation (c.913insT) was found. No mutations were detected in their parents. Two patients had MECP2 mutations in the transcriptional repression domain (TRD). They had almost lost language functions and were found to have significantly delayed development compared with other patients.</p><p><b>CONCLUSIONS</b>Mutations in MECP2 gene were detected in 5 confirmed cases of Rett syndrome, and most of them were on exon 4. Mutations in the TRD of MECP2 protein may affect the language ability and development in children with Rett syndrome.</p>

Diagnosis of MECP2 duplication syndrome with molecular genetic techniques / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate whether the four boys with delayed motor development and intellectual disability suffer from MECP 2 duplication syndrome.</p><p><b>METHOD</b>Blood specimens and clinical data of four patients and mothers of patient 2 and patient 4 were collected. Genomic DNA was extracted from peripheral blood using DNA extraction kit. At first multiplex ligation-dependent probe amplification (MLPA) was employed in 4 patients, two distinct kits SALSA P036 and P070 for sub-telomere screening, and SALSA P245 for the 22 common microdeletion and microduplication syndromes. Then array-CGH analysis was carried out. Two mothers of patients were tested by array- comparative genomic hybridization (CGH) and X chromosome inactivation analysis.</p><p><b>RESULT</b>All the 4 patients presented with severe hypotonia, delayed motor development, intellectual disability and absent or limited language. Three patients manifested recurrent pneumonia in infancy except patient 2. Four patients had duplication on chromosome Xq28 with MLPA kit SALSA P245. Array-CGH identified the size of each duplication on Xq28. The precise size of each duplication was different in the four patients: patient 1, 14.931 Mb, patient 2, 0.393 Mb, patient 3, 0.482 Mb and patient 4, 0.299 Mb. To compare Xq28 duplications with UCSC database (http://genome.ucsc.edu/) revealed that each duplication harbors the MECP 2 and HCFC 1 gene. Mothers of patient 2 and patient 4 also carried microduplication on Xq28. X chromosome inactivation analysis demonstrated completely skewed inactivation (0: 100) and it is the inactive allele that passed on to the patients.</p><p><b>CONCLUSION</b>For patients that present with delayed motor development, intellectual disability, hypotonia, absent or limited language and recurrent infection, combination of MLPA and array- CGH is effective and specific diagnostic methods of MECP 2 duplication syndrome.</p>

Pulchinenoside control MeCP2 expression in FLS from RA model rats / 中国中药杂志

The role of pulchinenoside (PULC) in the regulation of MeCP2 expression was investigated in RA model rats. Adjuvant arthritis rats were used as RA model rats, and fibroblast-like synoviocytes (FLS) from the RA model rats were cultured. The effect of 100 mg x kg(-1) PULC gavage treatment on the MeCP2 expression and the effect of MeCP2 siRNA on the expression of SFRP2 and β-catenin were detected by real time qPCR and Western blotting. The role of PULC in the FLS proliferation was detected by MTT. The results showed that the MeCP2 expression was down-regulated, the SFRP2 expression was up-regulated and the FLS proliferation was inhibited in FLS after therapy. MeCP2 siRNA significantly inhibited the MeCP2 expression, up-regulated the SFRP2 expression and inhibited the β-catenin expression in FLS from RA model rats. PULC may increase the SFRP2 expression, inhibit the Wnt signaling and inhibit the FLS proliferation in FLS from the RA model rats by inhibiting the MeCP2 expression.

Genetic features and mechanism of Rett syndrome in Chinese population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the genetic characteristics and molecular mechanism of Chinese patients with Rett syndrome (RTT) and assess the recurrent risk in order to provide genetic counseling for the family with RTT patient.</p><p><b>METHODS</b>Methyl-CpG-binding protein 2 (MECP2) gene mutation analysis were performed on 405 Chinese RTT cases and 292 mothers of the patients with MECP2 mutations with polymerase chain reaction (PCR), direct sequencing and multiplex ligation-dependent probe amplification (MLPA). Then cyclin-dependent kinase-like 5 (CDKL5) and forkhead box protein G1 (FOXG1) genes mutation analysis were performed on the patients without MECP2 mutation. Parental origin of mutated MECP2 gene was detected with allele specific PCR analysis. Based on the difference methylation in CpG island of the first exon of human androgen-receptor gene on active and inactive X-chromosomes, methylation sensitive restriction endonuclease digestion was used to analyze the X-chromosome inactive (XCI) patterns.</p><p><b>RESULTS</b>MECP2 gene mutation was found in 86.9% RTT cases. CDKL5 gene mutation was found in only 3 cases with early-onset seizures variant. No FOXG1 mutation was found. There were 94.4% MECP2 mutations of paternal origin,and point mutations were common. However, microdeletions were common in maternal origin mutation. MECP2 gene mutation was found in only 1 (0.34%,1/292) mother with normal phenotype and non-random XCI pattern. Her daughter was a RTT patient with preserved speech variant, and her XCI pattern was random.</p><p><b>CONCLUSION</b>MECP2 is the main pathogenic gene in RTT. CDKL5 gene should be screened in patients with early-onset seizures variant without MECP2 gene mutation. The majority of RTT patients had paternally derived de novo MECP2 gene mutation, which may explain the high female to male ratio in RTT. Only 0.34% mothers carried the pathogenic mutation, indicating a lower recurrent risk for RTT families. The XCI may modulate the phenotype of RTT, so MECP2 gene mutation screening in the mothers is important for genetic counseling.</p>

Effect of DNA methyltransferase 1 and methyl-CpG-binding protein 2 abnormal expression on cervical lesions and related interaction / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the effect of DNA methyltransferase 1 (DNMT1) and methyl-CpG-binding protein 2 (MeCP2) on cervical cancer and cervix precancerous lesion.</p><p><b>METHODS</b>74 patients with cervix squamous cell carcinoma(SCC), 52 patients with cervical intraepithelial neoplasm I (CIN I), 60 patients with cervical intraepithelial neoplasm II - II (CIN II-III)and 58 patients with histologically diagnosed cervix inflammation(CI), were included in this study. Information as demography, reproductive history, life style, HPV infection were collected. Western Blot were used to detect the expression of DNMT1 protein and MeCP2 protein. Real-time PCR was used to detect the expression of DNMT1 and MeCP2 mRNA.</p><p><b>RESULTS</b>Levels of DNMT1 and MeCP2 protein expression increased gradually with the deterioration of cervical lesion (H = 94.33, P < 0.001;F = 21.580, P < 0.001). Along with the deterioration of cervical lesion, levels of DNMT1 and MeCP2 mRNA expression were gradually increasing( F = 4.758, P = 0.003; F = 7.804, P < 0.001). Data from Correlation analysis showed that both protein (r = 0.287, P < 0.001) and mRNA(r = 0.179, P = 0.005)were positive correlated with DNMT1 and MeCP2.</p><p><b>RESULTS</b>of our study indicated that there was an additive interaction between high-expression of DNMT1 protein and high-expression of MeCP2 protein in SCC or CIN II-III. However, there was an additive interaction between high-expression of DNMT1 mRNA and high-expression of MeCP2 mRNA in SCC or CIN II-III.</p><p><b>CONCLUSION</b>Results from our study revealed the fact that both high expression of DNMT1 protein and high expression of MeCP2 protein could increase the risk of cervix cancerization. According to our findings, there might be a synergistic action existed between DNMT1 and MeCP2 during the progression of cervix cancelation.</p>