Clinical and biological progress over 50 years in Rett syndrome

In the 50 years since Andreas Rett first described the syndrome that came to bear his name, and is now known to be caused by a mutation in the methyl-CpG-binding protein 2 (MECP2) gene, a compelling blend of astute clinical observations and clinical and laboratory research has substantially enhanced our understanding of this rare disorder. Here, we document the contributions of the early pioneers in Rett syndrome (RTT) research, and describe the evolution of knowledge in terms of diagnostic criteria, clinical variation, and the interplay with other Rett-related disorders. We provide a synthesis of what is known about the neurobiology of MeCP2, considering the lessons learned from both cell and animal models, and how they might inform future clinical trials. With a focus on the core criteria, we examine the relationships between genotype and clinical severity. We review current knowledge about the many comorbidities that occur in RTT, and how genotype may modify their presentation. We also acknowledge the important drivers that are accelerating this research programme, including the roles of research infrastructure, international collaboration and advocacy groups. Finally, we highlight the major milestones since 1966, and what they mean for the day-to-day lives of individuals with RTT and their families

p.R270X MECP2 mutation and mortality in Rett syndrome

Among cases in the Australian Rett Syndrome Database, the nonsense mutation p.R270X is one of the most commonly occurring single pathogenic MECP2 mutations. In two recent published reports of the MECP2 mutational spectrum the p.R270X appeared to be under represented. We hypothesised that increased mortality arising from this mutation may underlie this apparent discrepancy. We investigated our hypothesis in two independent study groups from Australia and the UK with prospective data collections (total n=524). Only females with Rett syndrome and an identified MECP2 mutation were included. Significant differences in survival were detected among Rett syndrome cases grouped for the eight most frequent mutations (log-rank v2 (7)=15.71, P=0.03). Moreover, survival among cases with p.R270X, when compared with survival among cases with all the other mutations was reduced (log-rank v2 (2)=6.94, P=0.01). Our observation of a reduced survival associated with the p.R270X mutation offers an explanation for the under representation of p.R270X in older subjects with Rett syndrome

Rett syndrome: clinical and molecular characterization of two Brazilian patients Síndrome de Rett: caracterização clínica e molecular de dois casos brasileiros

BACKGROUND: Rett syndrome (RS) is recognized as a pan-ethnic condition. Since the identification of mutations in the MECP2 gene, more patients have been diagnosed, and a broad spectrum of phenotypes has been reported. There is a lack of phenotype-genotype studies. OBJECTIVE: To describe two cases of Brazilian patients with identified MECP2 mutations. METHOD: We present two female Brazilian patients with RS. RESULTS: Both patients presented with regression at 2-3 years of age, when stereotypic hand movements, social withdrawal and postnatal deceleration of head growth rate were observed. Both patients presented verbal communication impairment. Case 1 had loss of purposeful hand movements, and severe seizure episodes. Case 2 had milder impairment of purposeful hand movements, and no seizures. They had different mutations, D97Y and R294X, found in exons 3 and 4 of MECP2 gene, respectively. CONCLUSION: Testing for MECP2 mutations is important to confirm diagnosis and to establish genotype/phenotype correlations, and improve genetic counseling.<br>CONTEXTO: Síndrome de Rett (RS) é doença pan-étnica de fenótipo bastante variado desde que foram identificadas mutações no gene MECP2 e um número maior de pacientes tem sido diagnosticadas. Existe uma demanda por estudos que investiguem a relação genótipo-fenotipo. OBJETIVO: Descrever dois casos brasileiros de RS com mutações identificadas. MÉTODO: Duas pacientes brasileiras com diagnóstico clínico-molecular de RS foram descritas buscando-se correlacionar genótipo-fenótipo. RESULTADOS: Ambas pacientes apresentaram regressão aos 2-3 anos de idade, movimentos esteriotipados de mãos, retraimento social e desaceleração do crescimento encefálico. Ambas apresentaram déficit de comunicação verbal. Caso 1 também apresentou perda dos movimentos manuais intencionados e crises convulsivas graves. Caso 2 apresentou-se com comprometimento parcial dos movimentos manuais e sem história de crise convulsiva. As mutações distintas, D97Y e R294X, foram encontradas respectivamente em exons 3 e 4 do gene MECP2. CONCLUSÃO: A investigacao de mutações no gene MECP2 é importante na confirmação diagnóstica, investigação genótipo-fenótipo, e aconselhamento genético em síndrome de Rett

Somatic Mosaicism For A Mecp2 Mutation Associated With Classic Rett Syndrome In A Boy

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