Allelic Forms Of The Fmr1 Gene

The FMR1 gene is an example of how a single gene can have different phenotypic effects. Indeed, since its discovery in 1991 it has revealed new facets: classic Fragile X syndrome (FXS), Fragile X premature ovarian insufficiency (FXPOI), Fragile X tremor-ataxia syndrome (FXTAS) and other emerging disorders from which we are continuously learning more about this gene. The chapters of this book provide an update of the different allelic forms of the FMR1 gene. Chapter 1 is a description of the classical Fragile X syndrome including clinical findings in males and females, the FMR1 gene, molecular bases, the FMRP protein, animal models, genetic counseling, newborn screening and diagnosis. Chapters 2 and 3 review the two main disorders associated with FMR1 premutation: FXPOI and FXTAS. FXPOI is a new clinical entity in which carrier premutation (PM) females present early ovarian dysfunction, with menopause occurring 5 years earlier than non-carrier family members. FXTAS is a late-onset inherited neuropsychiatric degenerative disorder that occurs predominantly in male carriers of the FMR1 premutation. Chapters 4 and 5 present the most recent advances in the current knowledge of other disorders associated with the FMR1 gene: Chapter 4 describes the psychopathological alterations of the different phenotypes associated with either premutation or full mutation. Chapter 5 is focused on the pathologies associated with the premutation such as fibromyalgia, thyroid disease and hypertension, among others. A comprehensive review of genetic counseling is done in Chapter 6 including all types of alleles related to the FMR1 gene and point mutations. Finally, although at present there is no treatment for any of these pathologies, an update of the clinical trials on therapies for all these FMR1 gene-related disorders and their current status is made in Chapter 7.

In Fragile X-Associated Tremor Ataxia Syndrome (FXTAS), the editors present information on all aspects of FXTAS, including clinical features and current supportive management, radiological, psychological, and pathological findings, genotype-phenotype relationships, animal models and basic molecular mechanisms. Genetic counseling issues are also discussed. The book should serve as a resource for professionals in all fields regarding diagnosis, management, and counseling of patients with FXTAS and their families, as well as presenting the molecular basis for disease that may lead to the identification of new markers to predict disease risk and eventually lead to target treatments.

This new book is an up-to-date review of the clinical, epidemiological, and cytogenetic aspects of the fragile X (Martin-Bell) syndrome--the most common genetic cause of mental retardation after Down syndrome. The book includes the latest research findings concerning diagnosis on the basis of the appearance of a fragile site in cultured lymphocytes. It assumes little prior knowledge of the subject, and provides a clearly written, easy-to-understand discussion previously unavailable in a single reference source. The book will be of special interest to molecular biologists, cytogeneticists, medical geneticists, and clinicians and other professionals working with the mentally handicapped.

In this thoroughly revised and expanded third edition of the highly praised classic, The Principles of Clinical Cytogenetics, a panel of hands-on experts update their descriptions of the basic concepts and interpretations involved in chromosome analysis to include the many advances that have occurred in the field. Among the highlights are a full chapter devoted to advances in chromosome microarray, soon to become a standard of care in this field, as well as an update on chromosome nomenclature as reflected in ISCN 2009. Other features include an update on automation to reflect the current state of the art, an update on hematopoietic neoplasms to reflect the new WHO guidelines, and updates on all regulatory changes that have been implemented. Cutting edge and readily accessible, The Principles of Clinical Cytogenetics, Third Edition offers physicians who depend on the cytogenetics laboratory for the diagnosis of their patients, students in cytogenetics programs, graduate and medical students studying for board examinations, cytogenetics technologists, and cytogeneticists a clear understanding of what happens in the cytogenetics laboratory to facilitate accurate and timely diagnoses.

Clear, understandable and concise with an accompanying internet guide, this is an unbeatable resource for learning, revision and staying up to date.

This new edition of Fragile X Syndrome includes updated information on the latest research findings -- especially in molecular biology -- as well as new photographs highlighting clinical features and thorough coverage of treatment and intervention, diagnosis, and research. Praise for the first edition: "Answers nearly all the questions that parents or clinicians might raise about fragile X syndrome....Can be recommended confidently as a thoroughly up-to-date, reliable, and informative account of the condition." -- Lancet "The clinical and cytogenetic material in this book is excellent and provides a strong background for physicians and students... Fragile X Syndrome still presents the best comprehensive treatment of this complex disorder. Physicians, students, and other interested professionals can either read this book from cover to cover or select the chapters that interest or apply to them." -- New England Journal of Medicine

Neuronal and Synaptic Dysfunction in Autism Spectrum Disorder and Intellectual Disability provides the latest information on Autism spectrum disorders (ASDs), the lifelong neurodevelopmental disorders that present in early childhood and affect how individuals communicate and relate to others and their surroundings. In addition, three quarters of ASD patients also manifest severe intellectual disability. Though certain genes have been implicated, ASDs remain largely a mystery, and research looking into causes and cellular deficits are crucial for better understanding of neurodevelopmental disorders. Despite the prevalence and insidious nature of this disorder, this book remains to be an extensive resource of information and background on the state of current research in the field. The book serves as a reference for this purpose, and discusses the crucial role synaptic activity plays in proper brain function. In addition, the volume discusses the neurodevelopmental synaptopathies and serves as a resource for scientists and clinicians in all biomedical science specialties. This research has been crucial for recent studies that have provided a rationale for the development of pharmacological agents able to counteract functional synaptic anomalies and potentially ameliorate some ASD symptoms. Introduces the genetic and non-genetic causes of autism and associated intellectual disabilities Describes the genes implicated in autistic spectrum disorders and their function Considers major individual genetic causes of autism, Rett syndrome, Fragile X syndrome, and other autism spectrum disorders, as well as their classification as synaptopathies Presents a thorough discussion of the clinical aspects of multiple neurodevelopmental disorders and the experimental models that exist to study their pathophysiology in vitro and in vivo, including animal models and patient-derived stem cell culture

Trinucleotide repeats are relatively common in the human genome. These simple repeats have received much attention since epoch-making discoveries were made that particular trinucleotide repeats are expanded in the causal genes of human hereditary neurological disorders. For example, the CGG repeat is expanded in fragile X syndrome at the 5' untranslated region (UTR) of its causal gene. In myotonic dystrophy, it is the CTG repeat that is expanded at the 3' UTR of its causal gene. The CAG repeat was also found expanded in coding regions of the genes responsible for X-linked spinal and bulbar muscular atrophy, Huntington’s disease, spinocerebellar ataxia, and other disorders. On the other hand, expansion of the GAA repeat was identified in the intron of the gene responsible for the Friedreich’s ataxia. For these trinucleotide repeat diseases, the longer the trinucleotide expansion, the earlier the age of onset and the more severe the syndrome. Thus, these findings that showed the intriguing link between a particular trinucleotide expansion and its associated neurological disorders have led to a new field of intensive study. Active research addressing the underlying mechanisms for trinucleotide repeat diseases has employed various approaches ranging from DNA biochemistry to animal models for the diseases. In particular, animal models for the triplet repeat diseases have provided excellent resources not only for understanding the mechanisms but also for exploring therapeutic interventions.