Onset Of Huntington's Disease Research Articles

Huntington's Disease Gene Hunters: An Expanding Tale.

Huntington's Disease Gene Hunters: An Expanding Tale.

Clinical progression over 2 years of 220 patients with late onset Huntington's disease

Late onset Huntington's disease (LoHD) occurring in tardive adulthood (≥ 60 years) is recently gaining attention. We examined LoHD patients' clinical, cognitive and behavioral data over 2 years to investigate disease progression.

DIAPHRAGMATIC CHOREA IN A PATIENT WITH HUNTINGTON'S DISEASE: A CASE REPORT

TOPIC: Pulmonary Physiology TYPE: Fellow Case Reports INTRODUCTION: Respiratory muscle weakness is known to occur in neurodegenerative disorders, including Huntington's disease (HD), and causes 25% of deaths in this population. Though diaphragmatic dystonia has been described in some neurodegenerative diseases, it has not been in HD. In general, little published data exists on overall respiratory function and diaphragmatic movement in HD. CASE PRESENTATION: We describe a 58-year-old male with HD, presenting with progressive dyspnea over 1 year and an accompanying choking sensation upon awakening. Cardiac evaluation with echocardiogram and dobutamine stress test revealed only left ventricular hypertrophy. Family history includes HD in his mother, diagnosed at autopsy age 72;an older brother with HD onset at 53 that died at 62;a maternal aunt with onset in her 50s that died in her 70s. His maternal grandmother and 2 other family members also had involuntary movements believed to be chorea. Most died from respiratory complications. Physical exam showed adequate air entry bilaterally, with clear breath sounds and decreased chest wall expansion. No abdominal paradox or diaphragm dysfunction was appreciated in supine or seated position. On walking oximetry, he became tachypneic and dyspneic after 2 minutes of walking, prompting him to stop. His saturation on room air did not drop below 96%. Heart rate increased to 110 beats per minute. Laboratory panel revealed hemoglobin 13.8 g/dl. A venous blood gas revealed pH 7.38 and pCO2 of 49.A dynamic digital chest radiography (DDR) was performed during two tidal breaths and a forced inspiratory and expiratory maneuver. This revealed decreased bilateral lung inflation. Diaphragmatic contours were elevated bilaterally with a mildly reduced excursion. During the breathing cycle multiple independent diaphragmatic contractions were appreciated on forced inspiration and exhalation resulting in paradoxical motion and dyssynchrony. There was exaggerated use of accessory muscles in the shoulder girdle as a compensatory mechanism. Spasms in the upper airway were also noted throughout the test. Because of covid restrictions, the patient is awaiting pulmonary function tests. DISCUSSION: DDR uniquely provides the opportunity to interrogate respiratory physiology and identify diaphragmatic abnormalities, such as coordination impairments and dyssynchrony compared to static chest radiography;with lower levels of radiation as used in video fluoroscopy. As previously described1, we suggest that the understanding of dyspnea in patients with neurologic disease is enhanced using DDR. CONCLUSIONS: We report the first case of diaphragmatic chorea in a patient with HD using DDR. Future studies are needed to better understand this newly recognized phenomenon of diaphragmatic discoordination and its association with shortness of breath. REFERENCE #1: O'Sullivan M, Singh A, Prime D, Moore J, Zink S. A Whole New Chest X-Ray. ATS 2019 ePoster Viewing Site. Published May 2019. Accessed April 28, 2021. https://cslide-us.ctimeetingtech.com/ats2019_eposter/attendee/eposter/poster/6529 DISCLOSURES: No relevant relationships by Norma Braun, source=Web Response No relevant relationships by Jose Concepcion, source=Web Response No relevant relationships by Natasha Garg, source=Web Response No relevant relationships by Mary O Sullivan, source=Web Response No relevant relationships by Valeria Santibanez, source=Web Response

Sleep disturbances by disease type and stage in Huntington's disease

IntroductionSleep disturbances are a common symptom in patients with Huntington's disease (HD). However, it is unclear when in the disease course of HD sleep disturbances become more frequent compared to the general population. This study investigated the frequency and odds of developing sleep disturbances between adults with HD or at-risk for HD and non-HD controls. MethodsParticipants from the Enroll-HD study were split by both disease type and disease severity using CAG length, diagnostic confidence level, and total functional capacity score. Multivariate logistic regression was used to calculate odds ratios adjusted for age, sex, tobacco and alcohol use, depression and psychosis scores, and cognition to compare HD groups to non-HD controls. Cox proportional hazards models and Kaplan Meier curves were used to determine differences in probabilities of developing sleep disturbances and how sleep disturbances are related to age at motor onset. ResultsThere were significant differences between HD participants and non-HD controls in both the disease type and disease stage analyses (p < 0.001). The odds of a sleep disturbance increased with worsening disease stage and was highest in those with juvenile HD. The development of a sleep disorder in manifest HD participants was observed to be around the time of disease onset. ConclusionsSleep disturbances are more frequent in HD patients than those without HD. There are also differences based on disease type and stage. This is supplemented by the finding that the onset of sleep disturbances occurs near the time of motor onset of HD.

Mutant Huntingtin Impairs Pancreatic β-cells by Recruiting IRS-2 and Disturbing the PI3K/AKT/FoxO1 Signaling Pathway in Huntington's Disease.

Patients with Huntington's disease (HD) have an increased incidence of diabetes. However, the molecular mechanisms of pancreatic β-cell dysfunction have not been entirely clarified. Revealing the pathogenesis of diabetes can provide a novel understanding of the onset and progression of HD, as well as potential clues for the development of new therapeutics. Here, we demonstrated that the mouse pancreatic insulinoma cell line NIT-1 expressing N-terminal mutant huntingtin (mHTT) containing 160 polyglutamine (160Q cells) displayed lower cell proliferative ability than the cells expressing N-terminal wild-type HTT containing 20 polyglutamine (20Q cells). In addition, 160Q cells were more prone to apoptosis and exhibited deficient glucose-stimulated insulin expression and secretion. Furthermore, insulin signaling molecule insulin receptor substrate 2 (IRS-2) expression decreased and was recruited into mHTT aggregates. Consequently, glucose stimulation failed to activate the downstream molecule phosphatidylinositol-3 kinase (PI3K) in 160Q cells, leading to reduced phosphorylation levels of serine-threonine protein kinase AKT and forkhead box protein O1 (FoxO1). These data indicate that activation of the glucose-stimulated PI3K/AKT/FoxO1 signaling pathway is significantly blocked in pancreatic β-cells in HD. Importantly, insulin treatment inhibited the aggregation of mHTT and significantly improved the activation of PI3K/AKT/FoxO1 signaling in 160Q cells. These results suggest that the inhibition of the PI3K/AKT/FoxO1 pathway might be due to the recruitment of IRS-2 into mHTT aggregates in HD β-cells, ultimately contributing to the impairment of pancreatic β-cells. In conclusion, our work provides new insight into the underlying mechanisms of the high incidence of diabetes and abnormal glucose homeostasis in HD.

Mild Cognitive Impairment as an Early Landmark in Huntington's Disease.

As one of the clinical triad in Huntington's disease (HD), cognitive impairment has not been widely accepted as a disease stage indicator in HD literature. This work aims to study cognitive impairment thoroughly for prodromal HD individuals with the data from a 12-year observational study to determine whether Mild Cognitive Impairment (MCI) in HD gene-mutation carriers is a defensible indicator of early disease. Prodromal HD gene-mutation carriers evaluated annually at one of 32 worldwide sites from September 2002 to April 2014 were evaluated for MCI in six cognitive domains. Linear mixed-effects models were used to determine age-, education-, and retest-adjusted cut-off values in cognitive assessment for MCI, and then the concurrent and predictive validity of MCI was assessed. Accelerated failure time (AFT) models were used to determine the timing of MCI (single-, two-, and multiple-domain), and dementia, which was defined as MCI plus functional loss. Seven hundred and sixty-eight prodromal HD participants had completed all six cognitive tasks, had MRI, and underwent longitudinal assessments. Over half (i.e., 54%) of the participants had MCI at study entry, and half of these had single-domain MCI. Compared to participants with intact cognitive performances, prodromal HD with MCI had higher genetic burden, worsened motor impairment, greater brain atrophy, and a higher likelihood of estimated HD onset. Prospective longitudinal study of those without MCI at baseline showed that 48% had MCI in subsequent visits and data visualization suggested that single-domain MCI, two-domain MCI, and dementia represent appropriate cognitive impairment staging for HD gene-mutation carriers. Findings suggest that MCI represents an early landmark of HD and may be a sensitive enrichment variable or endpoint for prodromal clinical trials of disease modifying therapeutics.

Effect of Body Weight on Age at Onset in Huntington Disease: A Mendelian Randomization Study.

ObjectiveWeight loss is associated with clinical progression in Huntington disease (HD), but whether body weight causally affects disease onset or progression is unknown. Therefore, we aimed to assess whether genetically determined variations in body weight are causally related to age at onset in HD.MethodsUsing data from different recent genome-wide association studies, we performed a 2-sample mendelian randomization (MR) analysis to assess whether genetic markers of body mass index (BMI) are causally related to residual age at onset in HD, i.e., the difference between observed and expected age at onset based on mutation size. Our study had a statistical power of 90% to detect a causal effect of ≥3.8 months per BMI unit change at a type I error rate of 0.05.ResultsInverse-variance weighted MR estimates showed that a higher genetically determined BMI was not causally related to residual age at onset in HD (β = −0.44 years per unit increase in BMI, confidence interval: −1.33 to 0.46, p = 0.34). All other complementary (nonparametric) MR regression methods yielded similar results.ConclusionsAlthough maintaining a healthy and stable body weight remains important in patients with HD, promoting weight gain with the aim of delaying disease onset or slowing down disease progression should be discouraged. Our findings point toward the existence of underlying pathologic processes that dictate both the rate of clinical progression and weight loss in HD, which need further elucidation as targeting these pathways, rather than body weight per se, could be of therapeutic value.

Robust Optimization and Data Classification for Characterization of Huntington Disease Onset via Duality Methods

The features that characterize the onset of Huntington disease (HD) are poorly understood yet have significant implications for research and clinical practice. Motivated by the need to address this issue, and the fact that there may be inaccuracies in clinical HD data, we apply robust optimization and duality techniques to study support vector machine (SVM) classifiers in the face of uncertainty in feature data. We present readily numerically solvable semi-definite program reformulations via conic duality for a broad class of robust SVM classification problems under a general spectrahedron uncertainty set that covers the most commonly used uncertainty sets of robust optimization models, such as boxes, balls, and ellipsoids. In the case of the box-uncertainty model, we also provide a new simple quadratic program reformulation, via Lagrangian duality, leading to a very efficient iterative scheme for robust classifiers. Computational results on a range of datasets indicate that these robust classification methods allow for greater classification accuracies than conventional support vector machines in addition to selecting groups of highly correlated features. The conic duality-based robust SVMs were also successfully applied to a new, large HD dataset, achieving classification accuracies of over 95% and providing important information about the features that characterize HD onset.

It Is Time to Define Huntington's Disease Onset more Clearly.

It Is Time to Define Huntington's Disease Onset more Clearly.

Central Cognitive Processing Speed Is an Early Marker of Huntington's Disease Onset.

Several studies have suggested that cognitive processing speed may be useful for assessing early cognitive change in premanifest Huntington's disease (HD); however, current measures lack the ability to control for the effects of motor dysfunction commonly found in HD. The Computerized Test of Information Processing (CTiP) is a rapidly administered computerized tool that allows for the examination of central cognitive processing speed by using motor-corrected scores to account for motor dysfunction. To examine central cognitive processing speed as an early marker of HD onset using the CTiP. The CTiP and other measures were administered to 102 HD gene carriers and 55 healthy adults (HA). Gene carriers included presymptomatic HD (pre-HD; n = 33), prodromal HD (pro-HD; ie, individuals close to disease onset; n = 23), and mild-moderate HD (HD; n = 46). The HD group performed significantly slower than all other groups (HA, pre-HD, and pro-HD) on most subtests (Ps < .05). Moreover, the pro-HD group performed significantly slower than the HA group on both motor-corrected subtests (Ps < 0.05). Effect sizes associated with significant group differences between the pro-HD and HA groups on motor-corrected CTiP subtests (d = 0.73 and 0.84) were similar to effect sizes associated with group differences on the Symbol Digit Modalities Test (d = .82) and other traditional cognitive assessments (Montreal Cognitive Assessment, d = .75; Mini-Mental State Examination, d = .84). The CTiP may be a useful marker of deficits in central cognitive processing speed in individuals close to manifest onset of HD.

The Role of the Cerebellum in Huntington's Disease: a Systematic Review.

Huntington's disease (HD) is a rare neurological disorder characterized by progressive motor, cognitive, and psychiatric disturbances. Although striatum degeneration might justify most of the motor symptoms, there is an emerging evidence of involvement of extra-striatal structures, such as the cerebellum. To elucidate the cerebellar involvement and its afferences with motor, psychiatric, and cognitive symptoms in HD. A systematic search in the literature was performed in MEDLINE, LILACS, and Google Scholar databases. The research was broadened to include the screening of reference lists of review articles for additional studies. Studies available in the English language, dating from 1993 through May 2020, were included. Clinical presentation of patients with HD may not be considered as the result of an isolated primary striatal dysfunction. There is evidence that cerebellar involvement is an early event in HD and may occur independently of striatal degeneration. Also, the loss of the compensation role of the cerebellum in HD may be an explanation for the clinical onset of HD. Although more studies are needed to elucidate this association, the current literature supports that the cerebellum may integrate the natural history of neurodegeneration in HD.

The Interaction of Aging and Cellular Stress Contributes to Pathogenesis in Mouse and Human Huntington Disease Neurons.

Huntington disease (HD) is a fatal, inherited neurodegenerative disorder caused by a mutation in the huntingtin (HTT) gene. While mutant HTT is present ubiquitously throughout life, HD onset typically occurs in mid-life. Oxidative damage accumulates in the aging brain and is a feature of HD. We sought to interrogate the roles and interaction of age and oxidative stress in HD using primary Hu97/18 mouse neurons, neurons differentiated from HD patient induced pluripotent stem cells (iPSCs), and the brains of HD mice. We find that primary neurons must be matured in culture for canonical stress responses to occur. Furthermore, when aging is accelerated in mature HD neurons, mutant HTT accumulates and sensitivity to oxidative stress is selectively enhanced. Furthermore, we observe HD-specific phenotypes in neurons and mouse brains that have undergone accelerated aging, including a selective increase in DNA damage. These findings suggest a role for aging in HD pathogenesis and an interaction between the biological age of HD neurons and sensitivity to exogenous stress.

Fiberoptic endoscopic evaluation of swallowing in early-to-advanced stage Huntington\u2019s disease

Huntington's disease (HD) is a neurodegenerative disorder characterized by motor disturbances, cognitive decline, and behaviour changes. A well-recognized feature of advanced HD is dysphagia, which leads to malnutrition and aspiration pneumonia, the latter being the primary cause of death in HD. Previous studies have underscored the importance of dysphagia in HD patients with moderate-to-advanced stage disease, but it is unclear whether dysphagia affects patients already at an early stage of disease and whether genetic or clinical factors can predict its severity. We performed fiberoptic endoscopic evaluation of swallowing (FEES) in 61 patients with various stages of HD. Dysphagia was found in 35% of early-stage, 94% of moderate-stage, and 100% of advanced-stage HD. Silent aspiration was found in 7.7% of early-stage, 11.8% of moderate-stage, and 27.8% of advanced-stage HD. A strong correlation was observed between disease progression and dysphagia severity: worse dysphagia was associated with worsening of motor symptoms. Dysphagia severity as assessed by FEES correlated with Huntington’s Disease Dysphagia Scale scores (a self-report questionnaire specific for evaluating swallowing in HD). The present findings add to our understanding of dysphagia onset and progression in HD. A better understanding of dysphagia onset and progression in HD may inform guidelines for standard clinical care in dysphagia, its recognition, and management.

Huntington’s Disease: Les Jeux Sont Faits?

In a meticulous study, Humbert, Durr, and colleagues showed evidence for aberrant neurodevelopment in both Huntington's disease (HD) and mouse models of HD. We consider the implications of prenatal pathological changes for the onset and progression of HD and their relatedness to current therapeutic plans.

Gene expression profiles complement the analysis of genomic modifiers of the clinical onset of Huntington disease.

Huntington disease (HD) is a neurodegenerative disorder that is caused by a CAG repeat expansion in HTT. The length of this repeat, however, only explains a proportion of the variability in age of onset in patients. Genome-wide association studies have identified modifiers that contribute toward a proportion of the observed variance. By incorporating tissue-specific transcriptomic information with these results, additional modifiers can be identified. We performed a transcriptome-wide association study assessing heritable differences in genetically determined expression in diverse tissues, with genome-wide data from over 4000 patients. Functional validation of prioritized genes was undertaken in isogenic HD stem cells and patient brains. Enrichment analyses were performed with biologically relevant gene sets to identify the core pathways. HD-associated gene coexpression modules were assessed for associations with neurological phenotypes in an independent cohort and to guide drug repurposing analyses. Transcriptomic analyses identified genes that were associated with age of HD onset and displayed colocalization with gene expression signals in brain tissue (FAN1, GPR161, PMS2, SUMF2), with supporting evidence from functional experiments. This included genes involved in DNA repair, as well as novel-candidate modifier genes that have been associated with other neurological conditions. Further, cortical coexpression modules were also associated with cognitive decline and HD-related traits in a longitudinal cohort. In summary, the combination of population-scale gene expression information with HD patient genomic data identified novel modifier genes for the disorder. Further, these analyses expanded the pathways potentially involved in modifying HD onset and prioritized candidate therapeutics for future study.

Behavioral Deficits in Juvenile Onset Huntington's Disease.

Reports of behavioral disturbance in Juvenile-Onset Huntington’s Disease (JOHD) have been based primarily on qualitative caregiver reports or retrospective medical record reviews. This study aims to quantify differences in behavior in patients with JOHD using informant- and self-report questionnaires. Informants of 21 children/young adults (12 female) with JOHD and 115 children/young adults (64 female) with a family history of Huntington’s Disease, but who did not inherit the disease themselves (Gene-Non-Expanded; GNE) completed the Behavior Rating Inventory of Executive Function (BRIEF) and the Pediatric Behavior Scale (PBS). Mixed linear regression models (age/sex adjusted) were conducted to assess group differences on these measures. The JOHD group had significantly higher scores, indicating more problems, than the GNE group on all BRIEF subscales, and measures of Aggression/Opposition and Hyperactivity/Inattention of the PBS (all p < 0.05). There were no group differences in Depression/Anxiety. Inhibit, Plan/Organize, Initiate, and Aggression/Opposition had significant negative correlations with Cytosine-Adenine-Guanine (CAG) repeat length (all p < 0.05) meaning that individuals with higher CAG repeats scored lower on these measures. There was greater discrepancy between higher informant-vs. lower self-reported scores in the JOHD group, supporting the notion of lack of insight for the JOHD-affected group. These results provide quantitative evidence of behavioral characteristics of JOHD.

Understanding HD Psychosis: An Analysis from the ENROLL-HD Database.

Background:Psychosis is considered rare in Huntington’s Disease, with an estimated prevalence of 3–11%. However, it has a profound impact on quality of life and disease burden. This study uses the Enroll-HD database to determine the prevalence, onset, and severity of psychosis in Huntington’s Disease and to determine demographic and disease characteristics associated with psychosis.Methods:Data were obtained from Enroll-HD. Adults with manifest Huntington’s Disease were included. Descriptive statistics were calculated. Simple logistic regression was used to calculate the odds ratio with 95% confidence interval for association with each characteristic.Results:7,966 manifest Huntington’s Disease participants were analyzed, and 12.95% had a history of psychosis. Mean age of psychosis onset (48.34 years, SD 13.26) mirrored Huntington’s Disease onset. Family history of psychosis in a first degree relative was documented in 23.6% of participants with psychosis. Variables significantly (p < 0.05) associated with presence of psychosis in manifest HD included lower education level, unemployment, single marital status, depression, decreased verbal fluency score, and decreased total functional capacity & functional assessment score.Discussion:Psychosis in Huntington’s Disease is more prevalent than many prior studies have reported. It is associated with several demographic & psychiatric features, decreased cognitive capacity, and worse functional outcomes.Highlights:Psychosis in HD is more prevalent than prior studies have reported. It is associated with a range of demographic and psychiatric variables, worse cognition, and worse functional outcomes suggesting several features that may be used to predict onset of psychosis and improve understanding and management of psychosis in HD.

Genetic and Functional Analyses Point to FAN1 as the Source of Multiple Huntington Disease Modifier Effects

A recent genome-wide association study of Huntington disease (HD) implicated genes involved in DNA maintenance processes as modifiers of onset, including multiple genome-wide significant signals in a chr15 region containing the DNA repair gene Fanconi-Associated Nuclease 1 (FAN1). Here, we have carried out detailed genetic, molecular, and cellular investigation of the modifiers at this locus. We find that missense changes within or near the DNA-binding domain (p.Arg507His and p.Arg377Trp) reduce FAN1's DNA-binding activity and its capacity to rescue mitomycin C-induced cytotoxicity, accounting for two infrequent onset-hastening modifier signals. We also idenified a third onset-hastening modifier signal whose mechanism of action remains uncertain but does not involve an amino acid change in FAN1. We present additional evidence that a frequent onset-delaying modifier signal does not alter FAN1 coding sequence but is associated with increased FAN1 mRNA expression in the cerebral cortex. Consistent with these findings and other cellular overexpression and/or suppression studies, knockout of FAN1 increased CAG repeat expansion in HD-induced pluripotent stem cells. Together, these studies support the process of somatic CAG repeat expansion as a therapeutic target in HD, and they clearly indicate that multiple genetic variations act by different means through FAN1 to influence HD onset in a manner that is largely additive, except in the rare circumstance that two onset-hastening alleles are present. Thus, an individual's particular combination of FAN1 haplotypes may influence their suitability for HD clinical trials, particularly if the therapeutic agent aims to reduce CAG repeat instability.

Early Intrathecal T Helper 17.1 Cell Activity in Huntington Disease.

Huntington disease (HD) is an autosomal dominantly inherited neurodegenerative disorder caused by a CAG repeat expansion in the huntingtin (HTT) gene. No disease-modifying therapy exists for the treatment of patients with HD. The purpose of this study was therefore to investigate early disease mechanisms that potentially could be used as a target therapeutically. Lymphocyte activity in cerebrospinal fluid (CSF) from 4 cohorts of HTT gene expansion carriers (n = 121 in total) and controls was analyzed by techniques based on flow cytometry and enzyme-linked immunosorbent assays. The data of this study provide evidence of immune abnormalities before motor onset of disease. In CSF of HTT gene expansion carriers, we found increased levels of proinflammatory cytokines, including IL-17, and increased consumption of the lymphocyte growth factor IL-7 before motor onset of HD. In concordance, we observed an increased prevalence of IL-17-producing Th17.1 cells in the CSF of HTT gene expansion carriers, predominantly in pre-motor manifest individuals. The frequency of intrathecal Th17.1 cells correlated negatively with progression of HD and the level of neurodegeneration, suggesting a role of Th17.1 cells in the early disease stage. We also observed a skewing in the balance between proinflammatory and regulatory T cells potentially favoring a proinflammatory intrathecal environment in HTT gene expansion carriers. These data suggest that Th17.1 cells are implicated in the earliest pathogenic phases of HD and suggest that treatment to dampen T -cell-driven inflammation before motor onset might be of benefit in HTT gene expansion carriers. ANN NEUROL 2020;87:246-255.

Early epigenomic and transcriptional changes reveal Elk-1 transcription factor as a therapeutic target in Huntington’s disease

Huntington's disease (HD) is a chronic neurodegenerative disorder characterized by a late clinical onset despite ubiquitous expression of the mutant Huntingtin gene (HTT) from birth. Transcriptional dysregulation is a pivotal feature of HD. Yet, the genes that are altered in the prodromal period and their regulators, which present opportunities for therapeutic intervention, remain to be elucidated. Using transcriptional and chromatin profiling, we found aberrant transcription and changes in histone H3K27acetylation in the striatum of R6/1 mice during the presymptomatic disease stages. Integrating these data, we identified the Elk-1 transcription factor as a candidate regulator of prodromal changes in HD. Exogenous expression of Elk-1 exerted beneficial effects in a primary striatal cell culture model of HD, and adeno-associated virus-mediated Elk-1 overexpression alleviated transcriptional dysregulation in R6/1 mice. Collectively, our work demonstrates that aberrant gene expression precedes overt disease onset in HD, identifies the Elk-1 transcription factor as a key regulator linked to early epigenetic and transcriptional changes in HD, and presents evidence for Elk-1 as a target for alleviating molecular pathology in HD.