April 2026: This Month in Huntington’s Disease Research

April brought us advancements in Huntington’s disease (HD) research, from mouse studies targeting the disease at its source, to new technology that can reshape how we measure HD, and a better understanding of the impact it has on the whole family. We also unpacked the TFC score at the heart of the Phase 3 INVEST-HD trial and launched Fund the Buzz, our spring fundraising campaign. Let’s get into what we learned this month!

Themes That Unified the Month

Targeting HD at the source 

Two articles this month took aim at the root cause of HD rather than its downstream consequences. The HTT1a mouse study and the CRISPR study are asking the same fundamental question from different angles: if we can reduce or eliminate the most toxic form of huntingtin before it does its damage, can we change the course of HD? Early answers, at least in mice, are encouraging.

Technology is reshaping how we measure HD

Two articles explored the expanding role of Artificial Intelligence (AI) in the HD space – one grounded in a specific wearables study, the other surveying the field broadly. Together they capture a field increasingly capable of measuring HD where it actually lives: in everyday movement, in real time, outside the clinic. The measurement tools we build now will determine what we can detect in tomorrow’s trials.

The human cost of HD extends to everyone in the family

April brought two caregiver-focused studies, and their findings are strikingly consistent. The researchers report that caregivers are often isolated, under-supported by healthcare systems, and carrying practical, emotional, and relational burdens that remain largely invisible. Both studies highlight the need for better clinician education, accessible psychological support, and more honest conversations.

Understanding HD Biology

Blocking a toxic fragment

A new study published in Brain used CRISPR tools to engineer mice that make far less of HTT1a, a small, highly toxic fragment of the huntingtin protein. This culprit is generated when the expanded CAG repeat triggers the cell to stop making the full-length protein too early. When HTT1a levels were reduced, protein clumping was delayed by months, changes in genetic messages were partially reversed, and biomarkers like NfL returned toward normal. The results suggest HTT1a isn’t just a byproduct of the HD mutation, but potentially a central driver of disease, with implications for which HTT-lowering therapies are most likely to work. However, it’s important to remember that these results come from mice that model the disease, and much remains to be understood about HTT1a in people.

Cutting to the chase with CRISPR

A study in Science Advances used CRISPR molecular scissors to disrupt the expanded huntingtin gene in HD mice, reducing toxic protein levels by up to 90% and improving movement and lifespan as a result. A key design feature is that the system is self-inactivating, switching itself off after editing to reduce the risk of unintended cuts elsewhere in the genetic code. Even when mice were treated after symptoms were already established, benefits were still seen. Important hurdles remain before CRISPR approaches could be used in people, including safe delivery to the much-larger human brain and selective targeting of only the expanded gene copy, but this is an exciting step forward.

Technology in HD Research

Your Wrist on Watch

A study published in Communications Medicine asked people with HD to wear a Fitbit-like wrist sensor for seven days at home. Using AI to analyze the data, researchers found that people with HD showed slower, jerkier arm movements, with fewer long reaches, and AI approaches made these patterns automatically detectable from sensor data. A machine learning model correctly identified HD 72% of the time. The study is small, but it’s proof of concept for a technology that could transform how we measure drug effects in trials. MEND-HD, a fully remote follow-up study, is actively recruiting – visit mend-hd.com to learn more.

Artificial Intelligence Enters the HD Space as a Diagnostic Tool

While the wearables article zoomed in on one study, this broader review takes stock of AI’s growing role across HD research. One study used genetic data from 9,000 people with HD to identify modifier genes that influence age of onset, including some missed by earlier analyses. Another team trained an AI model on brain scans and clinical data to predict symptom onset 24% better than previous methods, which could sharpen clinical trial recruitment. A major current limitation is that the most powerful AI models can’t explain their reasoning, which is a real barrier to clinical use, but interpretable models are an active area of development. The HD community’s strong participation in natural history studies gives the field a competitive advantage, because good data means better models.

Clinical Trial Updates

What the TFC Score Measures, and Why It Matters Right Now

The Total Functional Capacity (TFC) scale rates functional ability across five domains (work, finances, household chores, daily living, and care needs) on a 0–13 scale. A score of 13 means fully functional; 0 means full-time nursing care. This explainer breaks down what TFC actually measures (capacity, not life circumstances), where it sits within the HD Integrated Staging System, and why it’s at the center of the Phase 3 votoplam trial INVEST-HD, which requires a TFC score of exactly 13 to enroll. That’s a narrower window than the previous Phase 2 PIVOT-HD trial of votoplam, which included people with TFC of 11, 12 or 13. However it’s important to remember that trial eligibility criteria are not the same as prescribing criteria, and if votoplam is approved, who can benefit will be a separate conversation. Check clinicaltrials.gov for site locations and talk to your HD specialist if you’d like more information.

Living with HD

Navigating Huntington’s Disease as a Caregiver

A small interview-based study listened to eleven adult caregivers of people with HD and identified three recurring themes: how caregiving reshapes relationships and identity over time, the persistent burden of stigma tied to HD’s hereditary nature, and major gaps in healthcare professionals’ knowledge of HD. Many caregivers reported that support from their communities existed more in theory than in practice, and that navigating healthcare systems felt like finding their way through a maze without signposts. The findings point to a need for better clinician training, more accessible psychological support, and recognition that caregiving for someone with HD is a long-term, compounding role.

Understanding Apathy in Huntington’s Disease Through Caregivers

Apathy in HD is not the same as sadness or low mood. It’s a loss of drive, initiative, and emotional responsiveness that can make a familiar person feel distant. A recent study interviewed eleven HD caregivers about their experiences of a loved one’s apathy.  They found five recurring themes: difficulty recognizing and naming apathy as a symptom, increased practical burden, emotional disconnection and relationship loss, a continuous, unpredictable grief, and a lack of safe spaces to speak honestly about their experience. Many caregivers described the research interviews themselves as a rare opportunity to voice feelings they had not permitted themselves to explore. The findings underscore a need for healthcare professionals to proactively explain apathy as a neurological symptom, and for accessible, judgment-free support for caregivers.

From HDBuzz

Fund the Buzz

This month HDBuzz launched Fund the Buzz, our spring fundraising campaign running through June 15, with a goal of $30,000. As an independent 501(c)(3), we rely entirely on community support – no pharmaceutical funding, no institutional safety net. That money goes to journalism insurance (~$8K/year, so we can report honestly on drug development and trial results without putting HDBuzz at risk), expanded editorial support (~$24K/year to keep pace with accelerating HD science), and website costs (~$9K/year to stay fast, accessible, and ad-free). If you value having a pharma-free, scientist-written source of HD news, please consider donating at hdbuzz.net/donate and share the campaign with your clinic, support group, and HD community.

Summary

• A mouse with reduced HTT1a (a toxic huntingtin fragment) showed delayed protein clumping, partial restoration of genetic message changes, and normalized biomarkers, suggesting HTT1a is a key disease driver, at least in mice
• A self-inactivating CRISPR system reduced expanded huntingtin by up to 90% in HD mice and improved motor symptoms and lifespan, even when given after disease onset
• A wrist-worn sensor tracked arm movements over seven days and correctly identified HD 72% of the time; the remote MEND-HD study is recruiting now at mend-hd.com 
• A broader review of AI in HD research covers genetic modifier identification, symptom onset prediction, and wearable-based movement tracking, with a note that HD’s rich natural history datasets give the field a real advantage
• An explainer on the TFC scale lays out what it measures, where it fits in the HD-ISS, and why INVEST-HD’s requirement of TFC = 13 is a narrower eligibility window than the Phase 2 trial
• A study of 11 HD caregivers identified themes of relationship transformation, genetic stigma, and healthcare gaps
• A study of 11 HD caregivers explored the experience of apathy in HD, highlighting emotional disconnection, compounding grief, and the need for safe spaces that allow honesty.
• HDBuzz launched Fund the Buzz, our spring campaign running through June 15, with a $30,000 goal – donate at hdbuzz.net/donate