Huntington's disease phenocopy syndromes revisited: a clinical comparison and next-generation sequencing exploration.

Background: Genetic testing for Huntington's disease (HD) was initially usually positive but more recently the negative rate has increased: patients with negative HD tests are described as having HD phenocopy syndromes (HDPC). This study examines their clinical characteristics and investigates the genetic causes of HDPC.

Methods: Clinical data from neurogenetics clinics and HDPC gene-panel data were analysed.

Long-Term Health Outcomes of Huntington Disease and the Impact of Future Disease-Modifying Treatments: A Decision-Modeling Analysis.

Background And Objectives: Disease-modifying treatments (DMTs) such as gene therapy are currently under investigation as a potential treatment for Huntington disease (HD). Our objective was to estimate the long-term natural history of HD progression and explore the potential efficacy impacts and value of a hypothetical DMT using a decision-analytic modeling framework.

Methods: We developed a health state transition model that separately analyzed 40-year-old individuals with prefunctional decline (PFD, HD Integrated Staging System [HD-ISS] stage <3, total functional score [TFC] 13), active functional decline Shoulson and Fahn category 1 (SF1, HD-ISS stage 3, TFC 13-11), and SF2 (HD-ISS stage 3, TFC 10-7).

Prognostic enrichment for early-stage Huntington's disease: An explainable machine learning approach for clinical trial.

Background: In Huntington's disease clinical trials, recruitment and stratification approaches primarily rely on genetic load, cognitive and motor assessment scores. They focus less on in vivo brain imaging markers, which reflect neuropathology well before clinical diagnosis. Machine learning methods offer a degree of sophistication which could significantly improve prognosis and stratification by leveraging multimodal biomarkers from large datasets.

Time to Functional Loss as an Endpoint in Huntington's Disease Trials: Enrichment and Sample Size.

Background: Clinical trial scenarios can be modeled using data from observational studies, providing critical information for design of real-world trials. The Huntington's Disease Integrated Staging System (HD-ISS) characterizes disease progression over an individual's lifespan and allows for flexibility in the design of trials with the goal of delaying progression. Enrichment methods can be applied to the HD-ISS to identify subgroups requiring smaller estimated sample sizes.

Outcomes of Percutaneous Endoscopic Gastrostomy in Huntington's Disease at a Tertiary Center.

Background: Clinically assisted nutrition and hydration via percutaneous endoscopic gastrostomy (PEG) is a therapeutic option to ameliorate the difficulties associated with enhanced catabolism, weight loss, and dysphagia in Huntington's disease (HD).

Objectives: The objective is to provide insights into demographics, staging (Shoulson-Fahn), complications, weight trajectories, and survival rates in people with HD (pwHD) who underwent PEG.

Methods: This retrospective study included 705 consecutive pwHD who attended our HD clinic between July 2006 and March 2024, of whom 52 underwent PEG.

Therapeutic validation of MMR-associated genetic modifiers in a human ex vivo model of Huntington disease.

The pathological huntingtin (HTT) trinucleotide repeat underlying Huntington disease (HD) continues to expand throughout life. Repeat length correlates both with earlier age at onset (AaO) and faster progression, making slowing its expansion an attractive therapeutic approach. Genome-wide association studies have identified candidate variants associated with altered AaO and progression, with many found in DNA mismatch repair (MMR)-associated genes.

Assessment of Perivascular Space Morphometry Across the White Matter in Huntington's Disease Using MRI.

Background: Perivascular spaces (PVS) are fluid-filled cavities surrounding small cerebral blood vessels. There are limited reports of enlarged PVS across the grey matter in manifest Huntington's disease (HD). Little is known about how PVS morphometry in the white matter may contribute to HD.

Huntington's Disease Clinical Trials Corner: March 2024.

In this edition of the Huntington's Disease Clinical Trials Update, we expand on the ongoing program from VICO Therapeutics and on the recently terminated VIBRANT-HD clinical trials. We also discuss updates from uniQure's AMT-130 program and PTC therapeutics' trial of PTC518 and list all currently registered and ongoing clinical trials in Huntington's disease.

Freesurfer Software Update Significantly Impacts Striatal Volumes in the Huntington's Disease Young Adult Study and Will Influence HD-ISS Staging.

Background: The Huntington's Disease Integrated Staging System (HD-ISS) defined disease onset using volumetric cut-offs for caudate and putamen derived from FreeSurfer 6 (FS6). The impact of the latest software update (FS7) on volumes remains unknown. The Huntington's Disease Young Adult Study (HD-YAS) is appropriately positioned to explore differences in FS bias when detecting early atrophy.

Safety and efficacy of laquinimod for Huntington's disease (LEGATO-HD): a multicentre, randomised, double-blind, placebo-controlled, phase 2 study.

Background: Laquinimod modulates CNS inflammatory pathways thought to be involved in the pathology of Huntington's disease. Studies with laquinimod in transgenic rodent models of Huntington's disease suggested improvements in motor function, reduction of brain volume loss, and prolonged survival. We aimed to evaluate the safety and efficacy of laquinimod in improving motor function and reducing caudate volume loss in patients with Huntington's disease.

The Huntington's Disease Gene Discovery.

The gene for Huntington's disease (HD) was discovered in 1993, after an international collaborative initiative that led researchers to remote regions of South America. It was the most remarkable milestone, since George Huntington's initial description. Through the phenomenological discussions led by Jean-Martin Charcot and Willian Osler, and finally Americo Negrette's reports, which served as the inspiration for the Venezuela Project led by Nancy Wexler, the journey toward discovering the Huntington's disease (HD) gene was marked by substantial efforts.

Complementary insights into corticostriatal synapse loss and cognition in Huntington's disease.

In a recent study, Wilton and colleagues link activation of the classical complement pathway with corticostriatal synapse loss and cognitive decline in Huntington's disease..

Genetic modifiers of repeat expansion disorders.

Repeat expansion disorders (REDs) are monogenic diseases caused by a sequence of repetitive DNA expanding above a pathogenic threshold. A common feature of the REDs is a strong genotype-phenotype correlation in which a major determinant of age at onset (AAO) and disease progression is the length of the inherited repeat tract. Over a disease-gene carrier's life, the length of the repeat can expand in somatic cells, through the process of somatic expansion which is hypothesised to drive disease progression.

The temporal event-based model: Learning event timelines in progressive diseases.

Timelines of events, such as symptom appearance or a change in biomarker value, provide powerful signatures that characterise progressive diseases. Understanding and predicting the timing of events is important for clinical trials targeting individuals early in the disease course when putative treatments are likely to have the strongest effect. However, previous models of disease progression cannot estimate the time between events and provide only an ordering in which they change.

Huntington's Disease Clinical Trials Corner: August 2023.

In this edition of the Huntington's Disease Clinical Trials Corner, we expand on the GENERATION HD2 (tominersen) and on the Asklepios Biopharmaceutical/BrainVectis trial with AB-1001. We also comment on the recent findings from the PROOF-HD trial, and list all currently registered and ongoing clinical trials in Huntington's disease.

Increased frequency of repeat expansion mutations across different populations.

Repeat expansion disorders (REDs) are a devastating group of predominantly neurological diseases. Together they are common, affecting 1 in 3,000 people worldwide with population-specific differences. However, prevalence estimates of REDs are hampered by heterogeneous clinical presentation, variable geographic distributions, and technological limitations leading to under-ascertainment.

Opportunity cost determines free-operant action initiation latency and predicts apathy.

Background: Apathy, a disabling and poorly understood neuropsychiatric symptom, is characterised by impaired self-initiated behaviour. It has been hypothesised that the (OCT) may be a key computational variable linking self-initiated behaviour with motivational status. OCT represents the amount of reward which is foregone per second if no action is taken.