Large-scale screening of clinical assessments to distinguish between states in the Integrated HD Progression Model (IHDPM).

Background: Understanding the sensitivity and utility of clinical assessments across different HD stages is important for study/trial endpoint selection and clinical assessment development. The Integrated HD Progression Model (IHDPM) characterizes the complex symptom progression of HD and separates the disease into nine ordered disease states. Objective: To generate a temporal map of discriminatory clinical measures across the IHDPM states. Methods: We applied the IHDPM to all HD individuals in an integrated longitudinal HD dataset derived from four observational studies, obtaining disease state assignment for each study visit. Using large-scale screening, we estimated Cohen's effect sizes to rank the discriminative power of 2,472 clinical measures for separating observations in disease state pairs. Individual trajectories through IHDPM states were examined. Discriminative analyses were limited to individuals with observations in both states of the pairs compared (N = 3,790). Results: Discriminative clinical measures were heterogeneous across the HD life course. UHDRS items were frequently identified as the best state pair discriminators, with UHDRS Motor items - most notably TMS - showing the highest discriminatory power between the early-disease states and early post-transition period states. UHDRS functional items emerged as strong discriminators from the transition period and on. Cognitive assessments showed good discriminative power between all state pairs examined, excepting state 1 vs. 2. Several non-UHDRS assessments were also flagged as excellent state discriminators for specific disease phases (e.g., SF-12). For certain state pairs, single assessment items other than total/summary scores were highlighted as having excellent discriminative power. Conclusion: By providing ranked quantitative scores indicating discriminatory ability of thousands of clinical measures between specific pairs of IHDPM states, our results will aid clinical trial designers select the most effective outcome measures tailored to their study cohort. Our observations may also assist in the development of end points targeting specific phases in the disease life course, through providing specific conceptual foci.

A Phenotypic Atlas for Huntington Disease Based on Data From the Enroll-HD Cohort Study.

Background and Objectives: The variable CAG repeat expansion in the huntingtin gene and its inverse relationship to motor dysfunction onset are fundamental features of Huntington disease (HD). However, the wider phenotype (including non-motor features) at particular CAG lengths, ages, and functional levels is less well-characterized. The large number of participants in the Enroll-HD observational study enables the development of a phenotype atlas that summarizes the range and distribution of HD phenotypes, including outliers and possible clusters, with respect to various CAG repeat lengths, age ranges, and declining functional levels. Methods: Enroll-HD is an ongoing prospective longitudinal observational study that collects natural history data, releasing periodic data sets, in people with HD (PwHD) and controls. Core assessments at annual visits focus on behavioral, cognitive, motor, and functional status. Periodic data set 5, used for the development of the first iteration of the Enroll-HD Phenotype Atlas (EHDPA), included all eligible data collected through October 31, 2020. The atlas is based on subsets (cells) of descriptive data for all motor, cognitive, psychiatric, and functional measures that are routinely collected at most Enroll-HD sites, analyzed by single CAG lengths and 5-year age blocks. Results: Data from 42,840 visits from 15,982 unique PwHD were available for analysis. At baseline, participants had a mean ± SD age of 48.9 ± 13.9 years and CAG repeat length of 43.4 ± 3.6 and 54.1% were female. The EHDPA includes 223 age-by-CAG subsets for CAG repeats between 36 and 69 with five-year age brackets starting from 20-24 years up to 85-89 years. The atlas can be browsed at enroll-hd.org/for-researchers/atlas-of-hd-phenotype/. Discussion: The EHDPA summarizes the spectrum and distribution of HD phenotypes, including outliers and possible clusters, in all domains of disease involvement for the range of CAG repeat lengths, ages, and functional levels. Its availability in an easy-to-use online format will assist clinicians in tracking disease progression in PwHD by identifying phenotypic features most associated with loss of function and enabling conversations related to prognosis. The observable patterns in the EHDPA should also catalyze more formal multidomain characterization of motor, cognitive, and psychiatric progression and their relationships to functional decline and disease modifiers. Trial Registration Information: Enroll-HD is registered with clinicaltrials.gov: NCT01574053.

Defining Clinical Meaningfulness in Huntington's Disease.

BACKGROUND: Minimal clinically important difference (MCID) represents the smallest within-person change on an outcome measure considered meaningful to the patient. Anchor-based MCID methods evaluate the relationship between changes in an outcome measure and the patient-reported clinical importance of that change. OBJECTIVE: This study aims to estimate longitudinal MCID for clinically relevant outcome measures for individuals who have Stages 2 or 3 disease as measured by the Huntington's Disease Integrated Staging System (HD-ISS). METHODS: Data were drawn from Enroll-HD, a large global longitudinal, observational study and clinical research platform for HD family members. We analyzed HD participants (N = 11,070) by staging group using time frames ranging from 12 to 36 months. The anchor was the physical component summary score of the 12-item short-form health survey. HD-relevant motor, cognitive, and functional outcome measures were independent, external criterion outcomes. Complex analysis was conducted using multiple, independent, linear mixed effect regression models with decomposition to calculate MCID for each external criterion by group. RESULTS: MCID estimates varied by progression stage. MCID estimates increased as stage progression increased and as the time frame increased. MCID values for key HD measures are provided. For example, starting in HD-ISS stage 2, meaningful group change over 24 months equals an average increase of 3.6 or more points on the Unified Huntington's Disease Rating Scale Total Motor Score. CONCLUSIONS: This is the first study to examine MCID estimation thresholds for HD. The results can be used to improve clinical interpretation of study outcomes and enable treatment recommendations to support clinical decision-making and clinical trial methodology. © 2023 International Parkinson and Movement Disorder Society.

Expanding the phenotypic spectrum of Dejerine-Sottas syndrome caused by the trembler mutation.

Dejerine-Sottas syndrome (DSS) is the earlier onset, more severe form of Charcot-Marie-Tooth (CMT) disease with heterogenous neurologic manifestations in addition to the peripheral neuropathy depending not only on the underlying causative gene but also the specific mutation. The Trembler mutation is an uncommon missense mutation in the PMP22 gene, the most commonly mutated gene responsible for CMT. We report two cases of DSS in a mother and son with the Trembler mutation, with associated findings of hearing loss and cognitive impairment. The mother had developmental gait abnormalities and became wheelchair bound in adolescence. She displayed impairment on cognitive and audiologic testing. Her son had similar developmental gait abnormalities and became wheelchair bound at age 19. Cognitive function showed an earlier decline in the son as compared to his mother. This report extends the clinical spectrum of the Trembler mutation in humans to include associated hearing loss with cognitive impairment.

Safety and Feasibility of Research Lumbar Puncture in Huntington's Disease: The HDClarity Cohort and Bioresource.

BACKGROUND: Biomarkers are needed to monitor disease progression, target engagement and efficacy in Huntington's disease (HD). Cerebrospinal fluid (CSF) is an ideal medium to research such biomarkers due to its proximity to the brain. OBJECTIVE: To investigate the safety and feasibility of research lumbar punctures (LP) in HD. METHODS: HDClarity is an ongoing international biofluid collection initiative built on the Enroll-HD platform, where clinical assessments are recorded. It aims to recruit 1,200 participants. Biosamples are collected following an overnight fast: blood via venipuncture and CSF via LP. Participants are healthy controls and HD gene expansion carriers across the disease spectrum. We report on monitored data from February 2016 to September 2019. RESULTS: Of 448 participants screened, 398 underwent at least 1 sampling visit, of which 98.24% were successful (i.e., CSF was collected), amounting to 10,610 mL of CSF and 8,200 mL of plasma. In the total 572 sampling visits, adverse events were reported in 24.13%, and headaches of any kind and post-LP headaches in 14.86% and 12.24%, respectively. Frequencies were less in manifest HD; gender, age, body mass index and disease burden score were not associated with the occurrence of the events in gene expansion carriers. Headaches and back pain were the most frequent adverse events. CONCLUSION: HDClarity is the largest CSF collection initiative to support scientific research into HD and is now stablished as a leading resource for HD research. Our data confirm that research LP in HD are feasible and acceptable to the community, and have a manageable safety profile.

A Machine-Learning Derived Huntington's Disease Progression Model: Insights for Clinical Trial Design.

BACKGROUND: Applying machine-learning algorithms to large datasets such as those available in Huntington's disease offers the opportunity to discover hidden patterns, often not discernible to clinical observation. OBJECTIVES: To develop and validate a model of Huntington's disease progression using probabilistic machine learning methods. METHODS: Longitudinal data encompassing 2079 assessment measures from four observational studies (PREDICT-HD, REGISTRY, TRACK-HD, and Enroll-HD) were integrated and machine-learning methods (Bayesian latent-variable analysis and continuous-time hidden Markov models) were applied to develop a probabilistic model of disease progression. The model was validated using a separate Enroll-HD dataset and compared with existing clinical reference assessments (Unified Huntington's Disease Rating Scale [UHDRS] diagnostic confidence level, total functional capacity, and total motor scores) and CAG-age product. RESULTS: Nine disease states were discovered based on 44 motor, cognitive, and functional measures, which correlated with reference assessments. The validation set included 3158 participants (mean age, 48.4 years) of whom 61.5% had manifest disease. Analysis of transition times showed that "early-disease" states 1 and 2, which occur before motor diagnosis, lasted ~16 years. Increasing numbers of participants had motor onset during "transition" states 3 to 5, which collectively lasted ~10 years, and the "late-disease" states 6 to 9 also lasted ~10 years. The annual probability of conversion from one of the nine identified disease states to the next ranged from 5% to 27%. CONCLUSIONS: The natural history of Huntington's disease can be described by nine disease states of increasing severity. The ability to derive characteristics of disease states and probabilities for progression through these states will improve trial design and participant selection. © 2021 International Parkinson and Movement Disorder Society.

Enroll-HD: An Integrated Clinical Research Platform and Worldwide Observational Study for Huntington's Disease.

Established in July 2012, Enroll-HD is both an integrated clinical research platform and a worldwide observational study designed to meet the clinical research requirements necessary to develop therapeutics for Huntington's disease (HD). The platform offers participants a low-burden entry into HD research, providing a large, well-characterized, research-engaged cohort with associated clinical data and biosamples that facilitates recruitment into interventional trials and other research studies. Additional studies that use Enroll-HD data and/or biosamples are built into the platform to further research on biomarkers and outcome measures. Enroll-HD is now operating worldwide in 21 countries at 159 clinical sites across four continents-Europe, North America, Latin America, and Australasia-and has recruited almost 25,000 participants, generating a large, rich clinical database with associated biosamples to expedite HD research; any researcher at a verifiable research organization can access the clinical datasets and biosamples from Enroll-HD and nested studies. Important operational features of Enroll-HD include a strong emphasis on standardization, data quality, and protecting participant identity, a single worldwide study protocol, a flexible EDC system capable of integrating multiple studies, a comprehensive monitoring infrastructure, an online portal to train and certify site personnel, and standardized study documents including informed consent forms and contractual agreements.

The Use of FDG PET Parametric Imaging in the Diagnosis of Olivopontocerebellar Atrophy.

Olivopontocerebellar atrophy is a rare neurodegenerative syndrome associated with 2 distinct disorders: multiple system atrophy and spinocerebellar ataxia. We present a case involving a 66-year-old man with adult-onset progressing cerebellar signs reflective of a cerebellar syndrome with no significant family history and unremarkable genetic testing for spinocerebellar ataxia. This case was found to be most consistent with sporadic olivopontocerebellar atrophy, which falls under the multiple system atrophy category. This diagnosis can be made using F-FDG PET/CT scanning and with MRI in some cases. However, in this case, relatively new PET/CT quantification and parametric imaging software was used for analysis, CortexID Suite.

Migraine and neurogenetic disorders.

In the current classification of headache disorders, headache attributable to genetic disorders is not classified separately, rather as headache attributed to cranial or cervical vascular disorder. The classification thus implies that a vascular pathology causes headache in these genetic disorders. Unquestionably, migraine is one of the prominent presenting features of several genetic cerebral small vessel diseases such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy, retinal vasculopathy with cerebral leukodystrophy, and hereditary infantile hemiparessis, retinal arteriolar tortuosity and leukoencephalopahty. Shared genetic features, increased susceptibility, and/or vascular endothelial dysfunction may play a role in pathogenesis of migraine. Common or overlapping pathways involving the responsible genes may provide insight regarding the pathophysiological mechanisms that can explain their comorbidity with migraine. This review focuses on clinical features of genetic vasculopathies. An independent category-migraine related to genetic disorders-should be considered to classify these disorders.

Parkinson's disease in patients and obligate carriers of Gaucher disease.

BACKGROUND: Gaucher disease is an autosomal recessive disorder caused by glucocerebrosidase gene mutations. Accumulating evidence from several Parkinson's disease cohorts of varying ethnicities suggests that glucocerebrosidase mutations even in the heterozygous state (carriers) may be a susceptibility factor for Parkinson's. Very few studies have analyzed the frequency of Parkinson's in carriers and individuals with Gaucher disease. OBJECTIVE: To determine frequency of Parkinson's in patients with Gaucher disease and obligate carriers of glucocerebrosidase mutations and compare it with a control group. METHODS: A questionnaire was completed by 100 Ashkenazi Jewish Gaucher patients followed at our center and 109 ethnicity-matched controls with no personal or family history of Gaucher disease. RESULTS: Frequency of Parkinson's was higher in Gaucher patients (8/100) than in controls (0/109; P = 0.0024). Frequency of Parkinson's in obligate carriers (11/200) was higher than controls (6/218), but the difference was not statistically significant (P = 0.215). Average age of onset of Parkinson's was earlier in Gaucher patients (57.2) than the general population and in obligate carriers (60) when compared with controls (76.8; P = 0.01). The L444P genotype was more frequent in Gaucher patients who reported a parent with Parkinson's (36.40%) than those who did not (4.50%). CONCLUSION: Our study suggests that the risk for developing Parkinson's may be higher in affected versus carriers of glucocerebrosidase mutations and suggests that L444P may pose a higher risk of developing Parkinson's than other mutations. It also confirms previous findings that the age of onset of Parkinson's associated with glucocerebrosidase mutations is earlier than in the general population.

The incidence of Parkinsonism in patients with type 1 Gaucher disease: data from the ICGG Gaucher Registry.

PURPOSE: Investigate the incidence of Parkinsonism among patients with Gaucher disease type 1 (GD1) and describe demographics, genotypes, and Gaucher disease (GD)-related characteristics for affected and non-affected patients. STUDY TYPE: Cohort study with age- and gender-matched nested case-control analysis. Calculation of event incidence, standardized morbidity ratio, and event-free survival (Kaplan-Meier). DATA SOURCE: The International Collaborative Gaucher Group (ICGG) Gaucher Registry data as of June 2010. Study cohort: GD1 patients with any report of Parkinsonism. Pre-matching control group: All GD1 patients with no report of Parkinsonism. RESULTS: The matched study cohort comprised of 68 patients with reports of Parkinsonism and 649 patients without Parkinsonism. Demographic and clinical characteristics suggest a milder GD phenotype in patients with Parkinsonism compared to the control group. The most prevalent GD1 genotype was N370S/N370S (39% for controls; 46% for patients with Parkinsonism). Patients with Parkinsonism were diagnosed with GD1 at a mean age of 37 years compared to 31 years in control patients. The standardized morbidity ratio for the development of Parkinsonism among all GD1 patients indicated an approximately 6 to 17 fold increase over that of 2 reference populations. The mean age of reported Parkinsonism onset was 57 years compared to 60 years in the general population (Lees, Hardy, and Revesz, 2009 [1]). The probability that a patient with GD1 will develop Parkinsonism before age 70 years is 5 to 7% and 9 to 12% before age 80 years. CONCLUSIONS: The incidence of Parkinsonism among GD1 patients is significantly increased compared to two reference populations. GD1 patients with Parkinsonism have a later median age at GD diagnosis, later age at the start of treatment, and later age at death than patients with GD1 alone. The Gaucher-related clinical profile of GD1 patients with Parkinsonism is similar to or milder than the GD1 alone group. Therefore, severity of the common GD1 clinical manifestations does not appear to be predictive for the onset of Parkinsonism.

An open-label Phase I/II clinical trial of pyrimethamine for the treatment of patients affected with chronic GM2 gangliosidosis (Tay-Sachs or Sandhoff variants).

Late-onset GM2 gangliosidosis is an autosomal recessive, neurodegenerative, lysosomal storage disease, caused by deficiency of ß-hexosaminidase A (Hex A), resulting from mutations in the HEXA (Tay-Sachs variant) or the HEXB (Sandhoff variant) genes. The enzyme deficiency in many patients with juvenile or adult onset forms of the disease results from the production of an unstable protein, which becomes targeted for premature degradation by the quality control system of the smooth endoplasmic reticulum and is not transported to lysosomes. In vitro studies have shown that many mutations in either the α or ß subunit of Hex A can be partially rescued, i.e. enhanced levels of both enzyme protein and activity in lysosomes, following the growth of patient cells in the presence of the drug, pyrimethamine. The objectives of the present clinical trial were to establish the tolerability and efficacy of the treatment of late-onset GM2 gangliosidosis patients with escalating doses of pyrimethamine, to a maximum of 100 mg per day, administered orally in a single daily dose, over a 16-week period . The primary objective, tolerability, was assessed by regular clinical examinations, along with a panel of hematologic and biochemical studies. Although clinical efficacy could not be assessed in this short trial, treatment efficacy was evaluated by repeated measurements of leukocyte Hex A activity, expressed relative to the activity of lysosomal ß-glucuronidase. A total of 11 patients were enrolled, 8 males and 3 females, aged 23 to 50 years. One subject failed the initial screen, another was omitted from analysis because of the large number of protocol violations, and a third was withdrawn very early as a result of adverse events which were not drug-related. For the remaining 8 subjects, up to a 4-fold enhancement of Hex A activity at doses of 50 mg per day or less was observed. Additionally marked individual variations in the pharmacokinetics of the drug among the patients were noted. However, the study also found that significant side effects were experienced by most patients at or above 75 mg pyrimethamine per day. We concluded that pyrimethamine treatment enhances leukocyte Hex A activity in patients with late-onset GM2 gangliosidosis at doses lower than those associated with unacceptable side effects. Further plans are underway to extend these trials and to develop methods to assess clinical efficacy.

Gaucher disease ascertained through a Parkinson's center: imaging and clinical characterization.

Among the genes implicated for parkinsonism is glucocerebrosidase (GBA), which causes Gaucher disease (GD). Despite a growing literature that GD may present as parkinsonism, neuroimaging, olfaction, and neuropsychological testing have not been extensively reported. We describe transcranial sonography (TCS), 18F-fluorodopa (F-dopa) and fluorodeoxyglucose (FDG) Positron emission tomography, olfaction testing, neuropsychological testing, and clinical features in homozygous and compound heterozygous GBA mutation carriers identified through screening of 250 Ashkenazi Jewish parkinsonian individuals treated at a tertiary care center. We identified two individuals with N370S/R496H compound heterozygous mutations and two with N370S homozygous mutations; one individual died before completing detailed evaluation. TCS (n = 3) demonstrated nigral hyperechogenicity that was greater than controls [median area maximal substantia nigra echogenicity (aSNmax) = 0.28 cm(2) vs. 0.14 cm(2), P = 0.005], but similar to idiopathic PD (aSNmax = 0.31 cm(2)). FDG PET (n = 2) demonstrated hypermetabolism of the lentiform nuclei, and F-fluorodopa PET (n = 2), bilateral reduction in striatal F-dopa uptake. Olfaction was markedly impaired in the two tested cases, including onset of smell disturbance in adolescence in one. Neuropsychological features (n = 3) were consistent with Parkinson's disease (PD) or diffuse Lewy body disease (DLB). The imaging, neuropsychological and olfactory markers suggest the GD phenotype includes PD with and without features of DLB, marked olfactory loss, nigral hyperechogenicity on TCS, and F-dopa and FDG PET abnormalities.

The risk of Parkinson's disease in type 1 Gaucher disease.

In Gaucher disease, defective lysosomal glucocerebrosidase due to mutations in the GBA1 gene results in lysosomal accumulation of glucocerebroside in mononuclear phagocytes and a multisystemic phenotype. Observations of occurrence of Parkinson's disease in some patients with non-neuronopathic type 1 Gaucher disease (GD1) and their first degree relatives has led to the identification of GBA1 heterozygous mutations as a genetic risk factor for idiopathic Parkinson's disease (PD). However, the magnitude of risk of PD in patients with known GD1 has not been determined, and it is not known whether GD1/PD represents a specific sub-phenotype of GD1 with distinctive genotype/phenotype characteristics. We estimated the risk of PD in a cohort of 444 consecutively evaluated patients with GD1 compared to that in the general population. Eleven patients developed parkinsonian syndrome during a 12-year follow-up period. The adjusted life-time risk ratio of PD in GD1 compared to that in the general population was 21.4 [95% confidence interval (95% CI) 10.7-38.3], with a higher risk in men compared to women. In our cohort, GD1/Parkinson's disease phenotype (GD1/PD) was characterized by higher GD1 severity score, due to higher incidence of avascular osteonecrosis. The clinical spectrum of PD varied from mild to potentially life-threatening disease. All but one patient with GD1/PD phenotype had at least one N370S GBA1 allele. In conclusion, compared to the general population, patients with GD1 have an almost 20-fold increased life-time risk of developing PD.

Head trauma can initiate the onset of adreno-leukodystrophy.

X-linked adreno-leukodystrophy and its adult variant, adrenomyeloneuropathy, are caused by mutations in ABCD1 that encodes a peroxisomal membrane protein of unknown physiological significance. In spite of identical mutations, they can have markedly divergent neurological and neuropathologic characteristics. Adreno-leukodystrophy classically presents in normal boys with mild neuropsychiatric features, which progress to frank neurological signs, the vegetative state and death in approximately three years. Adrenomyeloneuropathy typically affects young men with spastic paraparesis and sensory ataxia that can progress over decades. The neuropathologic correlate for adreno-leukodystrophy is severe inflammatory demyelination of posterior cerebral white matter, while a chronic distal axonopathy of spinal cord and peripheral nerve occurs in adrenomyeloneuropathy. Consequently, both modifier genes and environmental factors have been implicated in their pathogeneses. We report five cases of adreno-leukodystrophy whose onsets were initiated by moderate to severe head trauma, two of whom were conversions from adrenomyeloneuropathy. Their clinical courses were rapidly incapacitating, short (i.e., weeks to a few years) and fatal due to marked cerebral inflammatory demyelination. These cases, in concert with several previous reports, indicate that head trauma is one environmental factor that can have a profoundly deleterious effect on those genetically at risk for, or with milder clinical phenotypes of, this disease. Avoidance of potential head trauma and a rapid response to episodes of moderate to severe head trauma in this patient population seem prudent.

Acute confusional migraine may be a presenting feature of CADASIL.

OBJECTIVE: Characterize the phenomenon of acute confusional migraine (ACM) among Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) patients and emphasize the possibility of CADASIL in adults with ACM. BACKGROUND: ACM, well described in children, has rarely been reported in adults. Although 30-60% of CADASIL patients have migraine, acute confusional state during migraine has not been described. We describe 7 patients with ACM that complicated up to 50% of the migraine episodes. DESIGN/METHODS: Detailed neurologic evaluation was performed in 20 CADASIL patients; International Classification of Headache Disorders 2nd edition criteria were used to diagnose migraine. RESULTS: The mean age was 51 years. Fourteen patients reported headache and 11 met the criteria for migraine (mean age of onset 25). Seven patients experienced concomitant confusion, within 3 years of migraine onset. Confusion occurred either abruptly or insidiously, at the onset of aura or headache, lasting for 2-48 hours, and ending abruptly. These episodes were stereotypic, characterized by disorientation with agitation, and retrograde amnesia for the episodes. Patients reported disorientation to time and place, inability to recognize friends and relatives, difficulty with finding directions home, fear of getting lost, inability to analyze traffic lights or tell time. Patients reliably predicted the episodes and felt the need to seek a safe place for protection. Severity of the episodes progressed, but a striking improvement occurred after the first stroke. CONCLUSION: ACM may be a presenting feature and important clue, enabling CADASIL to be recognized up to a decade or earlier than at present. Therefore, a brain MRI and/or testing for Notch3 mutations should be considered in adult patients with ACM.