Trinucleotide Diseases And Instability

Till recently, mutations in genes were described in textbooks as deletions or point mutations. These mutations can be inherited from a parent or they are de novo alterations. The discovery in 1991 that human disease can be caused by large-scale ex pansion of highly unstable trinucleotide repeats has elucidated a new mutation mechanism, heritable unstable DNA. In the subsequent years more then 10 such disease genes have been identified. All dynamic mutations have been iden tified in neurological disorders. There are ten possible trinucleotide repeats at the DNA level, but only 3 have been identified as being involved in human dis eases. The rather frequent occurence of triplet repeats in the human genome indicates that other loci subject to unstable expansions may be discovered. The identification of repeat instability and the identification of disease genes containing trinucleotide repeats has helped to answer intriguing questions. The diseases share the unusual characteristic of inheritance with increased disease severity in successive gernerations, a phenomenon called anticipation. Trinu cleotide repeat diseases are ideal subjects for direct testing because the muta tion is almost exclusively of the same type and there is an extremely low occur ance of new mutations in these diseases. The anticipation can now be explained by the correlation of increasing repeat length with increased disease serverity. It can be speculated that other neurological disorders showing anticipation will be caused by unstable repeats as well.

World of Unstable Mutations The book "Triplet Repeat Diseases of the Nervous System" overviews the lat est data on several disorders associated with unstable mutations. This field of re search is progressing extremely fast. The number of polymorphic mutations and diseases caused by these mutations is increasing almost every month. There is a strong interest to molecular bases of triplet repeat disorders. This is explained by growing necessity to develop molecular approaches for cure of these diseases. There fore, the authors of this book describe unstable mutations with the emphasis on molecular pathology. Broad discussion is presented on how polymorphic expan sions cause cell dysfunction. o The first chapter of the book focuses on the molecular pathological pro cesses that originate "unstable" mutations. The authors review several avail able models by which normal "stable" region of DNA become pathogenic and discuss possible mechanisms causing DNA instability. o The other chapters of the book describe inherited diseases associated with different types of unstable mutations. Based on the location of mutation in the disease gene, polymorphic expansions of the nervous system can be divided into two major groups. First group includes disorders with unstable expansions within the open reading frame of the gene such as Spinocer ebellar Ataxias caused by polyglutamine expansions. The second group in cludes diseases caused by expansions situated within the untranslated re gions of the gene.

This heavily illustrated, must-have practical guide aids medical specialists and trainees in the diagnosis of neurodegenerative diseases. Includes diagnostic algorithms.

Huntington's disease (HD) is an inherited progressive neurodegenerative disorder. Although onset of Huntington's Disease usually occurs in adulthood, the age of onset of the condition is extremely variable with approximately 5-10% of cases having an onset of less than 20 years, or Juvenile Huntington's Disease (JHD). While JHD shares many of the clinical features of adult HD (e.g., chorea and personality disorders), patients with JHD often experience additional problems including seizures, dystonia and Parkinsonism. Diagnosis in patients with JHD is often delayed because of the failure of clinicians to recognise the characteristic features of the condition. While several textbooks have been published on HD, no books have been published to date focussing solely on the juvenile onset form of the disease. This book summarises, for the first time, the clinical and scientific knowledge available on JHD. It also collects together accounts from families affected by the condition, putting the clinical and scientific chapters into context. Edited by members of the working group on Juvenile Huntington's Disease within the European Huntington Disease Network (EHDN), this book forms the first comprehensive text on JHD and is of interest to neurologists, geneticists, academic/research scientists and other healthcare professionals.

World of Unstable Mutations The book "Triplet Repeat Diseases of the Nervous System" overviews the lat est data on several disorders associated with unstable mutations. This field of re search is progressing extremely fast. The number of polymorphic mutations and diseases caused by these mutations is increasing almost every month. There is a strong interest to molecular bases of triplet repeat disorders. This is explained by growing necessity to develop molecular approaches for cure of these diseases. There fore, the authors of this book describe unstable mutations with the emphasis on molecular pathology. Broad discussion is presented on how polymorphic expan sions cause cell dysfunction. o The first chapter of the book focuses on the molecular pathological pro cesses that originate "unstable" mutations. The authors review several avail able models by which normal "stable" region of DNA become pathogenic and discuss possible mechanisms causing DNA instability. o The other chapters of the book describe inherited diseases associated with different types of unstable mutations. Based on the location of mutation in the disease gene, polymorphic expansions of the nervous system can be divided into two major groups. First group includes disorders with unstable expansions within the open reading frame of the gene such as Spinocer ebellar Ataxias caused by polyglutamine expansions. The second group in cludes diseases caused by expansions situated within the untranslated re gions of the gene.

This book focuses on the discovery of a common genetic basis for a group of inherited neurological disorders, including Huntington's Disease, spino-bulbar atrophy and a series of hereditary ataxias. This shared molecular background and other similarities have led to the development of theoretical models for the pathogenesis of these diseases. It is now also clear that the mechanisms involved are likely to be of more general relevance, outside of this particular group of disorders, with implications for other neurodegenerative processes such as those involved in Alzheimer's, Parkinson's and Prion diseases. The book is an edited and updated compilation evolving from a Royal Society discussion meeting.

Genetic Instabilities and Neurological Diseases covers DNA repeat instability and neurological disorders, covering molecular mechanisms of repeat expansion, pathogenic mechanisms, clinical phenotype, parental gender effects, genotype-phenotype correlation, and diagnostic applications of the molecular data. This updated edition provides updates of these repeat expansion mutations, including the addition of many new chapters, and old chapters rewritten as extensions of the previous edition. This book is an invaluable reference source for neuroscientists, geneticists, neurologists, molecular biologists, genetic counsellors and students. Contributions by most of the principal research teams in the area, edited by world-renowned leaders Lays the background for future investigations on related diseases

This monograph describes the progress in neuropathological HD research made during the last century, the neuropathological hallmarks of HD and their pathogenic relevance. Starting with the initial descriptions of the progressive degeneration of the striatum as one of the key events in HD, the worldwide practiced Vonsattel HD grading system of striatal neurodegeneration will be outlined. Correlating neuropathological data with results on the functional neuroanatomy of the human brain, subsequent chapters will highlight recent HD findings: the neuronal loss in the cerebral neo-and allocortex, the neurodegeneration of select thalamic nuclei, the affection of the cerebellar cortex and nuclei, the involvement of select brainstem nuclei, as well as the pathophysiological relevance of these pathologies for the clinical picture of HD. Finally, the potential pathophysiological role of neuronal huntingtin aggregations and the most important and enduring challenges of neuropathological HD research are discussed.