No description available.

Thesis (Ph.D.) -- University of Rhode Island, 2008. / Typescript. Includes bibliographical references (leaves 149-169).

No description available.

Myoclonus-Dystonia (MD) is an inherited, rare, autosomal dominant movement disorder characterized by quick, involuntary muscle jerking or twitching (myoclonus) and involuntary muscle contractions that cause twisting and pulling movements, resulting in abnormal postures (dystonia). The first MD locus was mapped to 7q21-q31 and called DYT11; this locus corresponds to the SGCE gene. Our group previously identified a second MD locus (DYT15) which maps to a 3.18 Mb region on 18p11. Two patients were chosen to undergo next-generation sequencing, which identified 2,292 shared novel variants within the critical region. Analysis of these variants revealed a 3 bp duplication in a transcript referred to as CD108131, which is believed to be a long non-coding RNA. Characterization of this transcript determined that it is 863 bp in size, it is ubiquitously expressed, with high expression in the cerebellum, and it accounts for ~3% of MD cases.

Myoclonus-Dystonia (MD) is an inherited, rare, autosomal dominant movement disorder characterized by quick, involuntary muscle jerking or twitching (myoclonus) and involuntary muscle contractions that cause twisting and pulling movements, resulting in abnormal postures (dystonia). The first MD locus was mapped to 7q21-q31 and called DYT11; this locus corresponds to the SGCE gene. Our group previously identified a second MD locus (DYT15) which maps to a 3.18 Mb region on 18p11. Two patients were chosen to undergo next-generation sequencing, which identified 2,292 shared novel variants within the critical region. Analysis of these variants revealed a 3 bp duplication in a transcript referred to as CD108131, which is believed to be a long non-coding RNA. Characterization of this transcript determined that it is 863 bp in size, it is ubiquitously expressed, with high expression in the cerebellum, and it accounts for ~3% of MD cases.

Corticobasal Syndrome (CBS) is a rare movement and cognitive disorder. There is significant heterogeneity observed in it clinical presentation, neuroimaging, pathology and genetics. Understanding this heterogeneity is a priority and may help to shed light on underlying pathogenic mechanisms. We first demonstrated that truncating mutations in the progranulin gene (PGRN) can cause familial CBS associated with frontotemporal lobar degeneration (FTLD)-ubiquitin pathology. This study identified a mutation in PGRN (Intervening Sequence 7+1 guanine > adenine [IVS7+1G>A]) that segregated with CBS in a family. The mutation was predicted to result in a shortened messenger RNA (mRNA) sequence and the absence of the mutant PGRN allele was confirmed in the reverse transcriptase-polymerase chain reaction (RT-PCR) product, which supported the model of haploinsufficiency for PGRN-linked disease. In a second familial study, clinical, radiological, genetic, and pathological studies were performed to contrast clinical features of the affected members. Sequencing PGRN revealed a novel, heterozygous cytosine-adenine dinucleotide deletion in exon 11 (g.2988_2989delCA, P439_R440fsX6). The proband`s clinical diagnosis was frontotemporal dementia and parkinsonism (FTDP). The proband’s brother with the same mutation presented initially as a progressive non-fluent aphasia (PNFA), and later evolved into a CBS. Pathological analysis revealed Frontotemporal Lobar Degeneration-Ubiquitin (FTLD-U)/ TAR DNA-binding protein 43 (TDP43) positive pathology. The next studies shift away from pathogenic mechanisms to focus on brain-behavioural correlations and phenotypic heterogeneity in a prospective sample of 31 CBS cases. We provide the first direct correlative analysis between the severity of ideomotor apraxia, a common sign in CBS, and cerebral SPECT perfusion imaging. Reductions in perfusion within the left inferior parietal lobule (t=5.7, p=0.03, Family-Wise Error [FWE] corrected), including the left angular gyrus (t=5.7, p=0.02, FWE corrected), were associated with more severe ideomotor apraxia. We stratified the sample into CBS presenting with early motor features (CBS-M; n=9) or early dementia (CBS-D; n=22), which identified that CBS-M were more likely to have cortical sensory loss than CBS-D (p=0.005). In contrast, the presence of aphasia was found to be more common and severe in CBS-D compared to CBS-M (p=0.02). CBS-M patients had significantly reduced perfusion in the right supplementary and premotor areas compared to CBS-D (p<0.05).

Corticobasal Syndrome (CBS) is a rare movement and cognitive disorder. There is significant heterogeneity observed in it clinical presentation, neuroimaging, pathology and genetics. Understanding this heterogeneity is a priority and may help to shed light on underlying pathogenic mechanisms. We first demonstrated that truncating mutations in the progranulin gene (PGRN) can cause familial CBS associated with frontotemporal lobar degeneration (FTLD)-ubiquitin pathology. This study identified a mutation in PGRN (Intervening Sequence 7+1 guanine > adenine [IVS7+1G>A]) that segregated with CBS in a family. The mutation was predicted to result in a shortened messenger RNA (mRNA) sequence and the absence of the mutant PGRN allele was confirmed in the reverse transcriptase-polymerase chain reaction (RT-PCR) product, which supported the model of haploinsufficiency for PGRN-linked disease. In a second familial study, clinical, radiological, genetic, and pathological studies were performed to contrast clinical features of the affected members. Sequencing PGRN revealed a novel, heterozygous cytosine-adenine dinucleotide deletion in exon 11 (g.2988_2989delCA, P439_R440fsX6). The proband`s clinical diagnosis was frontotemporal dementia and parkinsonism (FTDP). The proband’s brother with the same mutation presented initially as a progressive non-fluent aphasia (PNFA), and later evolved into a CBS. Pathological analysis revealed Frontotemporal Lobar Degeneration-Ubiquitin (FTLD-U)/ TAR DNA-binding protein 43 (TDP43) positive pathology. The next studies shift away from pathogenic mechanisms to focus on brain-behavioural correlations and phenotypic heterogeneity in a prospective sample of 31 CBS cases. We provide the first direct correlative analysis between the severity of ideomotor apraxia, a common sign in CBS, and cerebral SPECT perfusion imaging. Reductions in perfusion within the left inferior parietal lobule (t=5.7, p=0.03, Family-Wise Error [FWE] corrected), including the left angular gyrus (t=5.7, p=0.02, FWE corrected), were associated with more severe ideomotor apraxia. We stratified the sample into CBS presenting with early motor features (CBS-M; n=9) or early dementia (CBS-D; n=22), which identified that CBS-M were more likely to have cortical sensory loss than CBS-D (p=0.005). In contrast, the presence of aphasia was found to be more common and severe in CBS-D compared to CBS-M (p=0.02). CBS-M patients had significantly reduced perfusion in the right supplementary and premotor areas compared to CBS-D (p<0.05).

The aim of this thesis was to investigate the neural underpinnings of persistent developmental stuttering. We explored neural systems important for speech-motor integration and focused on subcortical control systems: the basal ganglia and cerebellum. A secondary aim of this work was to distinguish effects related to general traits of the disorder from those reflecting specific states of stuttered speech. To address these aims we used a variety of neuroimaging methodologies as well as an extensive neuropsychological and empirical test battery. Our examination of neural pathway microstructure using diffusion-tensor imaging replicated previous findings of widespread disorganisation of white matter in people who stutter. This disruption included all major white matter pathways leading in and out of the cerebellum. In our second, third, and fourth studies we examined functional activity at rest and during different types of speech. The brain networks used by people who stutter and controls largely overlapped. The brain regions that distinguished general traits and specific states of stuttering were somewhat task-specific. Subcortical activation in the basal ganglia and cerebellum was related to the frequency of dysfluent speech in the scanner. In our final study we examined performance on a variety of classical tasks of motor learning. We observed evidence of delayed learning in response to changes in environmental feedback in the stuttering group relative to controls. Within people who stutter, subgroups who differ according to heritability of the disorder may also differ in the balance of dopamine in the basal ganglia. Overall, we concluded that cerebellar alterations contribute to the general trait of stuttering, while basal ganglia disruption may reflect specific effects within stuttering. Our work supports a broader role of the subcortical system in speech production, generally.

Myoclonus-Dystonia (MD) is an inherited, rare, autosomal dominant movement disorder characterized by quick, involuntary muscle jerking or twitching (myoclonus) and involuntary muscle contractions that cause twisting and pulling movements, resulting in abnormal postures (dystonia). The first MD locus was mapped to 7q21-q31 and called DYT11; this locus corresponds to the SGCE gene. Our group previously identified a second MD locus (DYT15) which maps to a 3.18 Mb region on 18p11. Two patients were chosen to undergo next-generation sequencing, which identified 2,292 shared novel variants within the critical region. Analysis of these variants revealed a 3 bp duplication in a transcript referred to as CD108131, which is believed to be a long non-coding RNA. Characterization of this transcript determined that it is 863 bp in size, it is ubiquitously expressed, with high expression in the cerebellum, and it accounts for ~3% of MD cases.

No description available.