A first for the CMT community

At our 2026 Clinical Trial Readiness Summit, CureCMT (HNF) became the first CMT organization to bring hearing testing on-site and to walk away with real research data because of it. Thanks to our patients, our sponsors, and our partnership with Shoebox, the screenings were free to the CMT community.

What our registry had already told us

Patients had been telling us about this for years. GRIN’s Hearing, Eyes, and Ears survey, part of the NIH-validated ClinGen survey set, collected complete responses from 445 people over the life of the registry:

  • Roughly 43% reported some degree of hearing impairment or loss
  • Nearly a quarter reported sensorineural hearing loss specifically, the type tied to the auditory nerve demyelination researchers believe drives CMT-related hearing changes
  • Close to 70% reported ringing in the ears
  • More than a third reported vertigo, and nearly 30% reported hyperacusis

Taken together, roughly two in three respondents reported at least one type of hearing loss, which lines up almost exactly with the ~50% rate the Summit screening turned up this spring.

Bar chart of self-reported hearing and ear symptoms from 445 GRIN registry participants: ringing in the ears 69.7%, hearing impairment or loss 42.5%, vertigo 37.6%, hyperacusis 29.4%, sensorineural hearing loss 23.8%, conductive hearing loss 11.3%, mixed hearing loss 7.5%. A marker shows the 2026 Summit clinical screening found about 50% with hearing loss.

What we found

Over 200 people came to the Summit in April. Thirty-one stepped up for the screening, many already suspecting something was off. Twenty-seven got an automatic result on the spot; the other four had a fuller conversation with a clinician because of more complex hearing histories.

Among the 27 automatic results:

  • 13 tested normal in both ears
  • 11 had some loss in both ears
  • 3 had loss in just one ear

That is roughly half the group showing some degree of hearing loss, well above what you would expect in the general population, and precisely in line with what our own GRIN data pointed to first.

Where loss showed up, it was mild to moderate; nobody screened came back with a severe result. And the pattern was consistent: hearing held up for lower and mid-range sounds but weakened as pitch climbed (think high-pitched beeps or birdsong). That’s the signature of a gradual, degenerative process, not sudden or noise-driven damage. Gradual, measurable, progressive: exactly the kind of signal a clinical trial endpoint needs.

Backed by published research

Our numbers are not an outlier. Hearing loss has been recognized as a genuine feature of CMT since the 1970s, and it appears often enough in CMT1A that a 2024 systematic review and meta-analysis treated it as a core finding across the literature. Our roughly 50% rate matches that body of research almost exactly.

The mechanism traces back to demyelination of the auditory nerve, a peripheral nerve, just like the ones CMT is known to affect. That explains the gradual, high-frequency pattern we saw at the Summit, and it’s a big part of why hearing could work as a sensitive, trackable signal of disease progression over time.

Why hearing could be the sharper signal

Current CMT outcome measures, strength, sensation, walking ability, can be slow to shift and hard to standardize across patients. Hearing is different: it’s objective, quantifiable, testable in minutes, and based on what we saw changes in a predictable, progressive pattern tied directly to the nerve damage at the heart of CMT. That combination is exactly what makes an outcome measure valuable in a clinical trial.

This is still pilot data

One Summit screening of 31 patients, paired with one cut of registry responses, is an important first signal, not a conclusion. Larger samples, clinical validation, and continued follow-up are all still needed before hearing loss can be treated as a confirmed, measurable feature of CMT’s natural history. We are building toward that: a clear pathway to determine whether hearing loss can be validated as a qualifying endpoint, and more GRIN survey participation and on-site screening at every Summit from here.

If you have CMT, your data is part of this story

The single biggest way to help move this from a promising signal to a recognized outcome measure is simple: join GRIN and complete the Hearing, Eyes, and Ears survey, even if you don’t have hearing loss. It’s just as important to hear from patients without hearing changes as it is from those with them. We’re studying the full prevalence of hearing involvement in CMT and how it shows up across different variants and mutations, and that picture only comes together when everyone responds, not just the people who notice a problem.

Join GRIN. Free, confidential, and open to anyone diagnosed with CMT.

Why this matters for our partners

None of this happens without the partners who fund and staff it. What we found confirms that hearing changes are common enough, and consistent enough with published science and our own registry, to justify screening at every future Summit. Every Summit from here adds to the dataset, and that dataset is how hearing moves from an overlooked symptom to a recognized outcome measure in CMT clinical trials.

References

  • Charcot-Marie-Tooth Disease and Hearing Loss: A Systematic Review With Meta-Analysis (PubMed, 2024)
  • Audiological findings in the Charcot-Marie-Tooth Disease (PMC)