Cortical cell loss is a core feature of Huntington’s disease (HD), beginning many years before clinical motor diagnosis, during the premanifest stage. However, it is unclear how genetic topography... Show moreCortical cell loss is a core feature of Huntington’s disease (HD), beginning many years before clinical motor diagnosis, during the premanifest stage. However, it is unclear how genetic topography relates to cortical cell loss. Here, we explore the biological processes and cell types underlying this relationship and validate these using cell-specific post-mortem data.Eighty premanifest participants on average 15 years from disease onset and 71 controls were included. Using volumetric and diffusion MRI we extracted HD-specific whole brain maps where lower grey matter volume and higher grey matter mean diffusivity, relative to controls, were used as proxies of cortical cell loss. These maps were combined with gene expression data from the Allen Human Brain Atlas (AHBA) to investigate the biological processes relating genetic topography and cortical cell loss.Cortical cell loss was positively correlated with the expression of developmental genes (i.e. higher expression correlated with greater atrophy and increased diffusivity) and negatively correlated with the expression of synaptic and metabolic genes that have been implicated in neurodegeneration. These findings were consistent for diffusion MRI and volumetric HD-specific brain maps.As wild-type huntingtin is known to play a role in neurodevelopment, we explored the association between wild-type huntingtin (HTT) expression and developmental gene expression across the AHBA. Co-expression network analyses in 134 human brains free of neurodegenerative disorders were also performed. HTT expression was correlated with the expression of genes involved in neurodevelopment while co-expression network analyses also revealed that HTT expression was associated with developmental biological processes.Expression weighted cell-type enrichment (EWCE) analyses were used to explore which specific cell types were associated with HD cortical cell loss and these associations were validated using cell specific single nucleus RNAseq (snRNAseq) data from post-mortem HD brains.The developmental transcriptomic profile of cortical cell loss in preHD was enriched in astrocytes and endothelial cells, while the neurodegenerative transcriptomic profile was enriched for neuronal and microglial cells. Astrocyte-specific genes differentially expressed in HD post-mortem brains relative to controls using snRNAseq were enriched in the developmental transcriptomic profile, while neuronal and microglial-specific genes were enriched in the neurodegenerative transcriptomic profile.Our findings suggest that cortical cell loss in preHD may arise from dual pathological processes, emerging as a consequence of neurodevelopmental changes, at the beginning of life, followed by neurodegeneration in adulthood, targeting areas with reduced expression of synaptic and metabolic genes. These events result in age-related cell death across multiple brain cell types. Show less
Ouwerkerk, J.; Feleus, S.; Zwaan, K.F. van der; Li, Y.L.; Roos, M.; Roon-Mom, W.M.C. van; ... ; Mina, E. 2023
Background In biomedicine, machine learning (ML) has proven beneficial for the prognosis and diagnosis of dif‑ferent diseases, including cancer and neurodegenerative disorders. For rare diseases,... Show moreBackground In biomedicine, machine learning (ML) has proven beneficial for the prognosis and diagnosis of dif‑ferent diseases, including cancer and neurodegenerative disorders. For rare diseases, however, the requirementfor large datasets often prevents this approach. Huntington’s disease (HD) is a rare neurodegenerative disorder causedby a CAG repeat expansion in the coding region of the huntingtin gene. The world’s largest observational studyfor HD, Enroll‑HD, describes over 21,000 participants. As such, Enroll‑HD is amenable to ML methods. In this study, wepre‑processed and imputed Enroll‑HD with ML methods to maximise the inclusion of participants and variables. Withthis dataset we developed models to improve the prediction of the age at onset (AAO) and compared it to the well‑established Langbehn formula. In addition, we used recurrent neural networks (RNNs) to demonstrate the utility of MLmethods for longitudinal datasets, assessing driving capabilities by learning from previous participant assessments.Results Simple pre‑processing imputed around 42% of missing values in Enroll‑HD. Also, 167 variables were retainedas a result of imputing with ML. We found that multiple ML models were able to outperform the Langbehn formula.The best ML model (light gradient boosting machine) improved the prognosis of AAO compared to the Langbehnformula by 9.2%, based on root mean squared error in the test set. In addition, our ML model provides more accu‑rate prognosis for a wider CAG repeat range compared to the Langbehn formula. Driving capability was predictedwith an accuracy of 85.2%. The resulting pre‑processing workflow and code to train the ML models are available to beused for related HD predictions at: https:// github. com/ Jaspe rO98/ hdml/ tree/ main.Conclusions Our pre‑processing workflow made it possible to resolve the missing values and include most par‑ticipants and variables in Enroll‑HD. We show the added value of a ML approach, which improved AAO predictionsand allowed for the development of an advisory model that can assist clinicians and participants in estimating futuredriving capability. Show less
Zande, N.A. van de; Bulk, M.; Najac, C.; Weerd, L. van der; Bresser, J. de; Lewerenz, J.; ... ; Bot, S.T. de 2023
IntroductionStrong evidence suggests a significant role for iron accumulation in the brain in addition to the well-documented neurodegenerative aspects of Huntington’s disease (HD). The putative... Show moreIntroductionStrong evidence suggests a significant role for iron accumulation in the brain in addition to the well-documented neurodegenerative aspects of Huntington’s disease (HD). The putative mechanisms by which iron is linked to the HD pathogenesis are multiple, including oxidative stress, ferroptosis and neuroinflammation. However, no previous study in a neurodegenerative disease has linked the observed increase of brain iron accumulation as measured by MRI with well-established cerebrospinal fluid (CSF) and blood biomarkers for iron accumulation, or with associated processes such as neuroinflammation. This study is designed to link quantitative data from iron levels and neuroinflammation metabolites obtained from 7T MRI of HD patients, with specific and well-known clinical biofluid markers for iron accumulation, neurodegeneration and neuroinflammation. Biofluid markers will provide quantitative measures of overall iron accumulation, neurodegeneration and neuroinflammation, while MRI measurements on the other hand will provide quantitative spatial information on brain pathology, neuroinflammation and brain iron accumulation, which will be linked to clinical outcome measures.MethodsThis is an observational cross-sectional study, IMAGINE-HD, in HD gene expansion carriers and healthy controls. We include premanifest HD gene expansion carriers and patients with manifest HD in an early or moderate stage. The study includes a 7T MRI scan of the brain, clinical evaluation, motor, functional, and neuropsychological assessments, and sampling of CSF and blood for the detection of iron, neurodegenerative and inflammatory markers. Quantitative Susceptibility Maps will be reconstructed using T2* weighted images to quantify brain iron levels and Magnetic Resonance Spectroscopy will be used to obtain information about neuroinflammation by measuring cell-specific intracellular metabolites’ level and diffusion. Age and sex matched healthy subjects are included as a control group.DiscussionResults from this study will provide an important basis for the evaluation of brain iron levels and neuroinflammation metabolites as an imaging biomarker for disease stage in HD and their relationship with the salient pathomechanisms of the disease on the one hand, and with clinical outcome on the other. Show less
Prins, S.; Borghans, L.; Kam, M.L. de; Groeneveld, G.J.; Gerven, J. van 2023
Background The prevalence of neurodegenerative diseases increases significantly with increasing age. Neurodegeneration is the progressive loss of function of neurons that eventually leads to cell... Show moreBackground The prevalence of neurodegenerative diseases increases significantly with increasing age. Neurodegeneration is the progressive loss of function of neurons that eventually leads to cell death, which in turn leads to cognitive disfunction. Cognitive performance can therefore also be considered age dependent. The current study investigated if the NeuroCart can detect age related decline on drug-sensitive CNS-tests in healthy volunteers (HV), and whether there are interactions between the rates of decline and sex. This study also investigated if the NeuroCart was able to differentiate disease profiles of neurodegenerative diseases, compared to age-matched HV and if there is age related decline in patient groups. Methods This retrospective study encompassed 93 studies, performed at CHDR between 2005 and 2020 that included NeuroCart measurements, which resulted in data from 2729 subjects. Five NeuroCart tests were included in this analysis: smooth and saccadic eye movements, body sway, adaptive tracking, VVLT and N-back. Data from 84 healthy male and female volunteer studies, aged 16-90, were included. Nine studies were performed in patients with Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD) or vascular dementia (VaD). The data were analyzed with regression analyses on age by group, sex, sex by age, group by sex and group by sex by age. Least square means (LSMs) and 95% confidence intervals (CIs) were calculated for each group at the average age of the group, and at the average age of each of the other groups, and per sex. Results Mean age and standard deviation (SD) for all groups was: HV 36.2 years (19.3), AD 68.3 years (8), PD 62.7 years (8.5), HD 51.4 years (9.8) and VaD 66.9 years (8.1). Performance on all NeuroCart tests decreased significantly each year in HV. Saccadic peak velocity (SPV) was increased in AD compared to age-matched HV (+26.28 degrees/s, p =0.007), while SPV was decreased for PD and HD compared to age-matched HV (PD: -15.87 degrees/s, p=0.038, HD: -22.52 degrees/s, p=0.018). In HD patients SPV decreased faster with age compared to HV. On saccadic peak velocity the slopes between HD vs HV were significantly different, indicating a faster decline in performance on this task for HD patients compared to HV per age year. Smooth pursuit showed an overall significant difference between subject groups (p=0.037. Significantly worse performance was found for AD (-12.87%, p=<0.001), PD (-4.45%, p=<0.001) and VaD (-5.69%, p=0.005) compared to age-matched HV. Body sway significantly increased with age (p=0.021). Postural stability was decreased for both PD and HD compared to age-matched HV (PD: +38.8%, p=<0.001, HD: 154.9%, p=<0.001). The adaptive tracking was significantly decreased with age (p=<0.001). Adaptive tracking performance by AD (-7.54%, p=<0.001), PD (-8.09%, p=<0.001), HD (-5.19%, p=<0.001) and VaD (-5.80%, p=<0.001) was decreased compared to age-matched HV. Adaptive tracking in PD patients vs HV and in PD vs HD patients was significantly different, indicating a faster decline on this task per age year for PD patients compared to HV and HD. The VVLT delayed word recall showed an overall significant effect of subject group (p=0.006. Correct delayed word recall was decreased for AD (-5.83 words, p=<0.001), HD (-3.40 words, p=<0.001) and VaD (-5.51 words, p=<0.001) compared to age-matched HV. Conclusion This study showed that the NeuroCart can detect age-related decreases in performance in HV, which were not affected by sex. The NeuroCart was able to detect significant differences in performance between AD, PD, HD, VaD and age-matched HV. Disease durations were unknown, therefore this cross-sectional study was not able to show age-related decline after disease onset. This article shows the importance of investigating age-related decline on digitalized neurocognitive test batteries. Performance declines with age, which emphasizes the need to correct for age when including HV in clinical trials. Patients with different neurogenerative diseases have distinct performance patterns on the NeuroCart , which this should be considered when performing NeuroCart tasks in patients with AD, PD, HD and VaD. Show less
The aim of this thesis is to explore fear of choking and fear of falling in people with Huntington's disease (HD) and their caregivers. Dysphagia and falls are common in HD and may lead to fear of... Show moreThe aim of this thesis is to explore fear of choking and fear of falling in people with Huntington's disease (HD) and their caregivers. Dysphagia and falls are common in HD and may lead to fear of choking and fear of falling. However, knowledge about this is mostly lacking, as well as knowledge about the relationship between cognitive and emotional factors and these types of fear. The study confirms that fall prevalence (29% over a 30-day period) and prevalence of dysphagia symptoms (90%) are high. However, a prevalence of about 50% is also reported for fear of choking and fear of falling in people with HD. However, their informal caregivers report the most fear. Severity of dysphagia symptoms was a predictor of fear of choking, and anticipatory awareness of fall risks and gender were found to be predictors of fear of falling. In most individuals with HD, a combination of preventive measures was used.Future research can improve both management of dysphagia and fear of choking and management of falls and fear of falling. Because questioning people with HD is sometimes difficult, due to speech and cognitive difficulties, diagnostic tools may be sought to facilitate this, such as wearable electronic devices. Show less
Background: Huntington's disease (HD) is a genetic, neurodegenerative disease. Due to the progressive nature of HD and the absence of a cure, (health-related) quality of life ((HR)QoL) is an... Show moreBackground: Huntington's disease (HD) is a genetic, neurodegenerative disease. Due to the progressive nature of HD and the absence of a cure, (health-related) quality of life ((HR)QoL) is an important topic. Several studies have investigated (HR)QoL in HD, yet a clear synthesis of the existing literature is lacking to date. We performed a systematic review on self-reported (HR)QoL, and factors and intervention effects associated with (HR)QoL in premanifest and manifest HD gene expansion carriers (pHDGECs and mHDGECs, respectively). Methods: PubMed, EMBASE, Web of Science, and PsycINFO were searched systematically from September 17th, 2021, up to August 11th, 2022. Methodological and conceptual quality of the included studies was assessed with two appraisal tools.Results: 30 out of 70 eligible articles were included. mHDGECs experienced lower (HR)QoL compared to pHDGECs and controls, whereas mixed findings were reported when compared to other neurological diseases. Several factors were associated with (HR)QoL that might contribute to lower (HR)QoL in mHDGECs, including depressive symptoms, physical and psychological symptoms, lower functional capacity, lower support, and unmet needs. Multidisciplinary rehabilitation programs and a respiratory muscle training were beneficial for (HR)QoL in mHDGECs. Discussion: (HR)QoL is experienced differently across the course of the disease. Although (HR)QoL is key for understanding the impact of HD and the effect of symptomatic treatment, there is a need to improve the methodological and conceptual shortcomings that were found in most studies, especially regarding the conceptual clarity when reporting on QoL and HRQoL. Suggestions for strengthening these shortcomings are provided in this review. Show less
Objectives: To explore the prevalence of dysphagia and fear of choking in patients with Huntington's disease (HD) as well as preventive measures, both those applied and those not included in... Show moreObjectives: To explore the prevalence of dysphagia and fear of choking in patients with Huntington's disease (HD) as well as preventive measures, both those applied and those not included in managing dysphagia. Also, to investigate related problems encountered by their formal and informal caregivers. Design: A multi-center observational cross-sectional study. Setting and Participants: 158 HD patients, recruited from six Dutch nursing homes specialized in HD, and their formal and informal caregivers Measurements: Patients were assessed by means of questionnaires enquiring about dysphagia, fear of choking and measures to manage dysphagia. Also, questionnaires were administered about awareness of dysphagia symptoms, cognition and anxiety. Because we expected individuals with greater care dependency to have a higher severity of dysphagia, we distinguished between a care-independent and a care-dependent group of HD patients. Results: In the total group, 90.5% of HD patients had one or more dysphagia symptoms. The prevalence of FoC in HD patients and the formal and informal caregivers' fears about choking in HD patients was 45.7%, 19.0% and 59.5%, respectively, for care-independent patients and 58.7%, 50.1% and 77.5% for care-dependent patients. The score on the Huntington's Disease Dysphagia Scale was a predictor for fear of FoC in care-independent patients. Speech-language therapy, supervision during eating and drinking and adaptation of food and drink consistency were the most frequently applied measures to manage dysphagia, a combination was used in most HD patients. Conclusions: In HD patients, the prevalence of dysphagia is high and fear of choking is common among both patients and caregivers. A more severe degree of dysphagia is a predictor of FoC in care-independent HD patients. A combination of measures was used to manage dysphagia in most HD patients. Show less
Petzke, T.M.; Rodriguez-Girondo, M.; Meer, L.B. van der 2022
Background: A positive predictive genetic test for Huntington's disease (HD) can be a life-changing event for both carriers and their partners, leading to lower wellbeing and increasing the risk... Show moreBackground: A positive predictive genetic test for Huntington's disease (HD) can be a life-changing event for both carriers and their partners, leading to lower wellbeing and increasing the risk for separation and divorce. The 'Hold me Tight' program (HmT), based on emotionally focused couples' therapy, aims at strengthening the couple bond by targeting attachment needs.Objective: This study investigates whether the HmT program helps couples strengthen their relationship, as an investment in a future where the disease will affect life in many ways.Methods: In a multiple baseline design using three baselines of varying length, 15 couples of presymptomatic HD-carriers and their partners were included. In three consecutive groups, couples underwent the intervention (an adapted version of the 8-session HmT program) in four weekly sessions and completed self-report questionnaires throughout the study period of 19 weeks (17 measurements). Attachment style was assessed at baseline, resilience at baseline and at the end of the follow-up, while relationship satisfaction and wellbeing were measured weekly. A multi-level model was applied to the data.Results: Over the course of the study, wellbeing and relationship satisfaction significantly improved; resilience, however, did not. Furthermore, all three outcome measures were moderated by attachment style, with more securely attached individuals showing better outcomes.Conclusion: HmT improved wellbeing and relationship satisfaction of couples facing HD. Due to these improvements and high patient acceptability rates, this program could become a standardized procedure in HD care. The program could be adapted for other populations, e.g., couples facing other genetic neurological disorders. Show less
Heinz, A.; Schilling, J.; Roon-Mom, W. van; Krauss, S. 2021
Huntington's disease (HD) is caused by an expansion mutation of a CAG repeat in exon 1 of the huntingtin (HTT) gene, that encodes an expanded polyglutamine tract in the HTT protein. HD is... Show moreHuntington's disease (HD) is caused by an expansion mutation of a CAG repeat in exon 1 of the huntingtin (HTT) gene, that encodes an expanded polyglutamine tract in the HTT protein. HD is characterized by progressive psychiatric and cognitive symptoms associated with a progressive movement disorder. HTT is ubiquitously expressed, but the pathological changes caused by the mutation are most prominent in the central nervous system. Since the mutation was discovered, research has mainly focused on the mutant HTT protein. But what if the polyglutamine protein is not the only cause of the neurotoxicity? Recent studies show that the mutant RNA transcript is also involved in cellular dysfunction. Here we discuss the abnormal interaction of the mutant HTT transcript with a protein complex containing the MID1 protein. MID1 aberrantly binds to CAG repeats and this binding increases with CAG repeat length. Since MID1 is a translation regulator, association of the MID1 complex stimulates translation of mutant HTT mRNA, resulting in an overproduction of polyglutamine protein. Thus, blocking the interaction between MID1 and mutant HTT mRNA is a promising therapeutic approach. Additionally, we show that MID1 expression in the brain of both HD patients and HD mice is aberrantly increased. This finding further supports the concept of blocking the interaction between MID1 and mutant HTT mRNA to counteract mutant HTT translation as a valuable therapeutic strategy. In line, recent studies in which either compounds affecting the assembly of the MID1 complex or molecules targeting HTT RNA, show promising results. Show less
Duijn, E. van; Fernandes, A.R.; Abreu, D.; Ware, J.J.; Neacy, E.; Sampaio, C. 2021
Background Risk of death from suicide in Huntington's disease is notably elevated relative to that in the general population, although the incidence within HD populations has not been precisely... Show moreBackground Risk of death from suicide in Huntington's disease is notably elevated relative to that in the general population, although the incidence within HD populations has not been precisely defined. Robust incidence estimates of suicidal behavior can serve as references for HD therapeutic research and post-marketing surveillance to help evaluate the suicidality risk of novel therapeutics. Aims To estimate the incidence rate of completed suicide and suicide attempt in the global, prospective HD cohort study Enroll-HD that records these events per protocol. Method A total of 20 912 participants were available for analysis (HD gene-expansion carriers (HDGECs) n = 15 924; non-HDGECs n = 4988) representing a collective observation period of 53 390 participant-years. Each observed event was subject to clinical review and evaluation. We generated incidence rates (events per 100 000 person-years) for suicides and suicide attempts using all available data, as well as by year of study and geographical region. Proportionate mortality statistics for suicide and respective 95% confidence intervals were also generated. Results The overall incidence rate of suicide in HDGECs was 72 per 100 000 person-years, and 8 per 100 000 person-years in non-HDGECs. Proportionate mortality attributable to suicide in HDGECs was 4.6%. For suicide attempts, the global overall incidence rate observed in HDGECs was 306-375 per 100 000 person-years, and 23-38 per 100 000 person-years in non-HDGECs. Conclusions The incidence estimates calculated here can be used as a reference to help evaluate drug safety and may also be useful in assessing progress in clinical care for HDGECs once therapeutic interventions become widely available. Show less
Sprenger, G.P.; Roos, R.A.C.; Zwet, E. van; Reijntjes, R.H.; Achterberg, W.P.; Bot, S.T. de 2021
Introduction: Pain could be an unknown non-motor symptom in Huntington's Disease (HD). The aim is therefore, to study the prevalence of pain interference, painful conditions and analgesic use... Show moreIntroduction: Pain could be an unknown non-motor symptom in Huntington's Disease (HD). The aim is therefore, to study the prevalence of pain interference, painful conditions and analgesic use across the different stages of HD and compare these levels to non-HD gene mutation carriers.Methods: A cross-sectional analysis of the Enroll-HD study was conducted in premanifest, manifest HD gene mutation carriers (n = 3989 and n = 7,485, respectively) and in non-HD gene mutation carriers (n = 3719). To investigate group differences, multivariable logistic regression analysis was performed with pairwise comparisons.Results: In the HD mutation carriers, the overall prevalence of pain interference was 34% (95% CI 31%-35%), of painful conditions 17% (95% CI 15%-19%) and analgesic use 13% (95% CI 11%-15%). Compared to non-mutation carriers, the prevalence of pain interference was significantly higher in the middle stage of HD (33% [95% CI 31%-35%] vs 42% [95% CI 39%-45%], P = 0,02), whereas the prevalence of painful conditions was significant lower in the late and middle stage of HD (17% [95% CI 16%-18%] vs 12% [95% CI 10%-14%], 15% [95% CI 13%-17%], P < 0,01]. No significant group difference was present in analgesic use.Conclusions: The prevalence of pain interference increases as HD progresses, however, the prevalence of painful conditions and analgesics do not increase accordingly. Further studies are necessary to investigate the aetiology of pain in HD and the risk for undertreatment of pain. Show less
Sprenger, G.P.; Roos, R.A.C.; Zwet, E. van; Reijntjes, R.H.; Achterberg, W.P.; Bot, S.T. de 2021
Introduction: Pain could be an unknown non-motor symptom in Huntington's Disease (HD). The aim is therefore, to study the prevalence of pain interference, painful conditions and analgesic use... Show moreIntroduction: Pain could be an unknown non-motor symptom in Huntington's Disease (HD). The aim is therefore, to study the prevalence of pain interference, painful conditions and analgesic use across the different stages of HD and compare these levels to non-HD gene mutation carriers.Methods: A cross-sectional analysis of the Enroll-HD study was conducted in premanifest, manifest HD gene mutation carriers (n = 3989 and n = 7,485, respectively) and in non-HD gene mutation carriers (n = 3719). To investigate group differences, multivariable logistic regression analysis was performed with pairwise comparisons.Results: In the HD mutation carriers, the overall prevalence of pain interference was 34% (95% CI 31%-35%), of painful conditions 17% (95% CI 15%-19%) and analgesic use 13% (95% CI 11%-15%). Compared to non-mutation carriers, the prevalence of pain interference was significantly higher in the middle stage of HD (33% [95% CI 31%-35%] vs 42% [95% CI 39%-45%], P = 0,02), whereas the prevalence of painful conditions was significant lower in the late and middle stage of HD (17% [95% CI 16%-18%] vs 12% [95% CI 10%-14%], 15% [95% CI 13%-17%], P < 0,01]. No significant group difference was present in analgesic use.Conclusions: The prevalence of pain interference increases as HD progresses, however, the prevalence of painful conditions and analgesics do not increase accordingly. Further studies are necessary to investigate the aetiology of pain in HD and the risk for undertreatment of pain. Show less
Background Cognitive impairment is a core feature of Huntington's disease (HD), however, the onset and rate of cognitive decline is highly variable. Apathy is the most common neuropsychiatric... Show moreBackground Cognitive impairment is a core feature of Huntington's disease (HD), however, the onset and rate of cognitive decline is highly variable. Apathy is the most common neuropsychiatric symptom of HD, and is associated with cognitive impairment. The aim of this study was to investigate apathy as a predictor of subsequent cognitive decline over 2 years in premanifest and early HD, using a prospective, longitudinal design. Methods A total of 118 premanifest HD gene carriers, 111 early HD and 118 healthy control participants from the multi-centre TRACK-HD study were included. Apathy symptoms were assessed at baseline using the apathy severity rating from the Short Problem Behaviours Assessment. A composite of 12 outcome measures from nine cognitive tasks was used to assess cognitive function at baseline and after 24 months. Results In the premanifest group, after controlling for age, depression and motor signs, more apathy symptoms predicted faster cognitive decline over 2 years. In contrast, in the early HD group, more motor signs, but not apathy, predicted faster subsequent cognitive decline. In the control group, only older age predicted cognitive decline. Conclusions Our findings indicate that in premanifest HD, apathy is a harbinger for cognitive decline. In contrast, after motor onset, in early diagnosed HD, motor symptom severity more strongly predicts the rate of cognitive decline. Show less
Background: Determination of disease onset in Huntington's disease is made by clinical experience. The diagnostic confidence level is an assessment regarding the certainty about the clinical... Show moreBackground: Determination of disease onset in Huntington's disease is made by clinical experience. The diagnostic confidence level is an assessment regarding the certainty about the clinical diagnosis based on motor signs. A level of 4 means the rater has >= 99% confidence motor abnormalities are unequivocal signs of disease. However, it does not state which motor abnormalities are signs of disease and how many must be present.Objective: Our aim is to explore how accurate the diagnostic confidence level is in estimating disease onset using the Enroll-HD data set. For clinical disease onset we use a cut-off total motor score >5 of the Unified Huntington's Disease Rating Scale. This score is used in the TRACK-HD study, with <= 5 indicating no substantial motor signs in premanifests.Methods: At baseline premanifest participants who converted to manifest (converters) and non-converters were compared for clinical symptoms and diagnostic confidence level. Clinical symptoms and diagnostic confidence levels were longitudinally displayed in converters.Results: Of 3731 eligible participants, 455 were converters and 3276 non-converters. Baseline diagnostic confidence levels were significantly higher in converters compared to non-converters (P < 0.001). 232 (51%) converters displayed a baseline motor score >5 (mean = 6.7). Converters had significantly more baseline clinical symptoms, and higher disease burden compared to non-converters (P < 0.001). Diagnostic confidence level before disease onset ranged between 1 and 3 in converters.Conclusions: According to this data the diagnostic confidence level is not an accurate instrument to determine phenoconversion. With trials evaluating disease modifying therapies it is important to develop more reliable diagnostic criteria. Show less
This thesis describes several aspects of diagnostic and therapeutic possibilities of mitochondrial function in clinical pharmacological. During several clinical studies in healthy volunteers, pre... Show moreThis thesis describes several aspects of diagnostic and therapeutic possibilities of mitochondrial function in clinical pharmacological. During several clinical studies in healthy volunteers, pre-frail elderly and Huntington’s disease patients, we used phosphorous magnetic resonance spectroscopy as the main method to measure mitochondrial function in vivo. Other in vivo methods included Near Infrared Spectroscopy and the novel Protoporphorin-9 Triplet State Lifetime Technique, besides in vitro ELISA methods to measure activity of separate complexes of the mitochondrial electron transport chain. Using these modalities, we showed mitochondrial dysfunction in pre-frail elderly, emphasizing the importance of an active lifestyle in the prevention of sarcopenia and frailty. Using the mitotoxicity of simvastatin, and its reversibility by ubiquinol, we validated the first proof-of-pharmacology model in healthy volunteers to evaluate efficacy of novel mitochondrial function improving compounds. We also described the importance of measuring (mitochondrial) oxygen consumption as a means to measure mitotoxicity of commonly described medications. Lastly, we evaluated the safety and efficacy of the novel compound SBT-020 in a placebo-controlled, double-blinded, randomized controlled trial in mild to moderate Huntington’s disease patients and compared central to peripheral mitochondrial function for the first time, gaining inside into therapeutic possibilities in this complex and devastating disease. Show less
Background The composite Unified Huntington's Disease Rating Scale (cUHDRS) is a multidimensional measure of progression in Huntington's disease (HD) being used as a primary outcome in clinical... Show moreBackground The composite Unified Huntington's Disease Rating Scale (cUHDRS) is a multidimensional measure of progression in Huntington's disease (HD) being used as a primary outcome in clinical trials investigating potentially disease-modifying huntingtin-lowering therapies.Objective Evaluating volumetric and structural connectivity correlates of the cUHDRS.Methods One hundred and nineteen premanifest and 119 early-HD participants were included. Gray and white matter (WM) volumes were correlated with cUHDRS cross-sectionally and longitudinally using voxel-based morphometry. Correlations between baseline fractional anisotropy (FA); mean, radial, and axial diffusivity; and baseline cUHDRS were examined using tract-based spatial statistics.Results Worse performance in the cUHDRS over time correlated with longitudinal volume decreases in the occipito-parietal cortex and centrum semiovale, whereas lower baseline scores correlated with decreased volume in the basal ganglia and surrounding WM. Lower cUHDRS scores were also associated with reduced FA and increased diffusivity at baseline.Conclusion The cUHDRS correlates with imaging biomarkers and tracks atrophy progression in HD supporting its biological relevance. (c) 2021 International Parkinson and Movement Disorder Society Show less
Zwaan, K.F. van der; Jacobs, M.; Zwet, E.W. van; Roos, R.A.C.; Bot, S.T. de 2021
Background: Huntington's disease (HD) is an inherited neurodegenerative disorder that is characterized by motor, cognitive, and psychiatric symptoms. Although 65% of HD expanded gene carriers... Show moreBackground: Huntington's disease (HD) is an inherited neurodegenerative disorder that is characterized by motor, cognitive, and psychiatric symptoms. Although 65% of HD expanded gene carriers report changes in employment as the first functional loss, little is known about the predictors leading to changes of working capacity. Given the impact on quality of life, understanding of these factors is of great clinical value.Objective: This study evaluates disease specific characteristics and their predictive value in loss of working capacity in HD.Methods: Longitudinal data was collected through the worldwide observational study (Enroll-HD), with 15,301 participants in total and 2,791 HD and healthy control participants meeting the inclusion criteria. Changes in working capacity were analyzed by means of a survival analysis. Predictive values of demographic factors and clinical characteristics were assessed for premanifest and manifest HD through Cox regressions.Results: HD expanded gene carriers, manifest and premanifest combined, had a 31% chance of experiencing changes in employment after three years, compared to 4% in healthy controls. Apathy was found to be the most crucial determinant of working capacity changes in premanifest HD, while executive and motor dysfunction play an important role in manifest HD.Conclusion: HD expanded gene carriers are more likely to lose working capacity compared to healthy controls. Disease progression, altered motor function, cognitive decline, and in an early stage of the disease apathetic symptoms are indicative of negative changes in working capacity. Clinicians should recognize that early disease related changes, especially apathy, can affect working capacity. Show less
Background: Falls are common in Huntington's disease (HD), which can have serious consequences and may therefore lead to fear of falling (FoF). There is little knowledge about falls or FoF in... Show moreBackground: Falls are common in Huntington's disease (HD), which can have serious consequences and may therefore lead to fear of falling (FoF). There is little knowledge about falls or FoF in individuals with HD or about formal and informal caregivers' fear about falls in individuals with HD.Objective: To explore prevalence of falls, FoF and fall preventive measures both those applied and those not included in managing falls in individuals with HD and their formal and informal caregivers, and to identify the relationship between FoF and, anxiety, awareness and cognitive functioning respectively.Methods: In a multi-center observational cross-sectional study, care-independent and -dependent individuals with HD and their formal and informal caregivers were recruited from six Dutch nursing homes specialized in HD. The participants were assessed by means of questionnaires enquiring about falls, FoF, awareness of fall risk, cognition, anxiety and fall preventive measures.Results: For all included 158 individuals with HD, the fall prevalence over the last 30 days was 28.8%. The prevalence of FoF in individuals with HD, formal caregivers and informal caregivers was 47.6%, 25.6%, and 63.5%, respectively, for care-independent individuals with HD and 46.9%, 26.3%, and 62.0%, respectively, for care-dependent individuals with HD. Anticipatory awareness of fall risks and gender are predictors of FoF in care-independent individuals with HD, though not in the care-dependent group. A combination of fall preventive measures is used in most individuals with HD.Conclusion: Fall prevalence is high and FoF is common in individuals with HD and their caregivers. Gender and anticipatory awareness are risk factors for FoF. In addition to the use of individual multifactorial fall prevention strategies, it is important to support both formal and informal caregivers in coping with falls. Show less
Neurodegenerative diseases are hallmarked by protein inclusions and cell loss in disease-related brain regions, but the molecular mechanisms that lead to the pathological and symptomatic hallmarks... Show moreNeurodegenerative diseases are hallmarked by protein inclusions and cell loss in disease-related brain regions, but the molecular mechanisms that lead to the pathological and symptomatic hallmarks of neurodegeneration are still not fully understood. In this thesis, we make use of bioinformatics approaches to analyze a high-resolution spatial gene expression atlas of the healthy human brain generated by the Allen Institute of Brain Science. Spatial transcriptomics allows examining the molecular and functional organization of the human brain and can be combined with neuroimaging data to identify brain regions and anatomical structures that are vulnerable to cell loss in neurodegenerative diseases. By combining both data modalities, we examined healthy molecular functions in brain regions associated with disease vulnerability based on neuroimaging features, namely gray matter loss within brain networks in individuals with Parkinson’s disease, Huntington’s disease, and individuals at risk of schizophrenia. With this thesis, we have shown that by applying data-driven computational methods we can explore the whole genome and find gene expression patterns informative of regional brain vulnerability in neurodegenerative diseases. Our methods can similarly be applied to unravel the molecular mechanisms in other neurodegenerative diseases, and potentially even reveal shared mechanisms between neurological disorders. Show less
Ellis, N.; Tee, A.; McAllister, B.; Massey, T.; McLauchlan, D.; Stone, T.; ... ; Holmans, P. 2020
BACKGROUND: Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an expanded CAG repeat in the HTT gene. It is diagnosed following a standardized examination of motor... Show moreBACKGROUND: Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an expanded CAG repeat in the HTT gene. It is diagnosed following a standardized examination of motor control and often presents with cognitive decline and psychiatric symptoms. Recent studies have detected genetic loci modifying the age at onset of motor symptoms in HD, but genetic factors influencing cognitive and psychiatric presentations are unknown.METHODS: We tested the hypothesis that psychiatric and cognitive symptoms in HD are influenced by the same common genetic variation as in the general population by 1) constructing polygenic risk scores from large genome-wide association studies of psychiatric and neurodegenerative disorders and of intelligence and 2) testing for correlation with the presence of psychiatric and cognitive symptoms in a large sample (n = 5160) of patients with HD.RESULTS: Polygenic risk score for major depression was associated specifically with increased risk of depression in HD, as was schizophrenia risk score with psychosis and irritability. Cognitive impairment and apathy were associated with reduced polygenic risk score for intelligence.CONCLUSIONS: Polygenic risk scores for psychiatric disorders, particularly depression and schizophrenia, are associated with increased risk of the corresponding psychiatric symptoms in HD, suggesting a common genetic liability. However, the genetic liability to cognitive impairment and apathy appears to be distinct from other psychiatric symptoms in HD. No associations were observed between HD symptoms and risk scores for other neurodegenerative disorders. These data provide a rationale for treatments effective in depression and schizophrenia to be used to treat depression and psychotic symptoms in HD. Show less
