Nerve Ultrasound in Acquired and Genetic Sensory Neuronopathies (GANECHO)

The Role of Nerve Ultrasound in Distinguishing Acquired and Genetic Sensory Neuronopathies (Ganglionopathy): A Multicenter Retrospective Study

Sensory neuronopathies (also called sensory ganglionopathies) are rare and heterogeneous disorders of genetic or acquired origin, caused by degeneration of the dorsal root ganglia. Their diagnosis currently relies on a combination of clinical evaluation and electrophysiological testing, as no specific biomarker is available.

Early diagnosis is particularly important in acquired forms, where early treatment can significantly influence prognosis.

Recent studies have reported a characteristic ultrasound pattern in several genetic sensory neuronopathies, showing abnormally small-caliber peripheral nerves in the upper limbs. However, these findings have only been described in genetic conditions. It is therefore unknown whether this ultrasound pattern is specific to genetic causes or may also occur in acquired sensory neuronopathies, especially those with long-standing evolution.

This retrospective multicenter study will analyze data already collected as part of routine care in approximately 50 patients with sensory neuronopathy. The objective is to compare nerve ultrasound findings between genetic and acquired forms, and to evaluate their association with clinical severity and electrophysiological parameters. Determining whether nerve atrophy observed on ultrasound is specific to genetic etiologies could help integrate ultrasound into the diagnostic workup, guiding the choice of complementary tests such as genetic analyses or early treatment initiation in acquired cases.

Study Overview

• Status: Not yet recruiting
• Conditions: Sensory Neuronopathy

Detailed Description

Sensory neuronopathies (also known as sensory ganglionopathies) constitute a rare and heterogeneous group of acquired and genetic disorders related to degeneration of the dorsal root ganglia. Diagnosis relies on clinical and electrophysiological features demonstrating a pure, non-length-dependent sensory involvement. At present, no specific biomarker exists, and diagnosis is based on a combination of clinical and electrophysiological criteria. Because sensory neuronopathies are disabling conditions, early diagnosis is crucial, particularly in acquired forms for which early treatment is an important prognostic factor.

Recently, several studies have reported a unique nerve ultrasound pattern in genetic sensory neuronopathies, showing reduced caliber of mixed peripheral nerves in the upper limbs. A recent literature review suggested that sufficient evidence exists to consider ultrasound as a potential marker of genetic sensory neuronopathies. However, these studies included only patients with genetic etiologies, and no data are currently available regarding ultrasound findings in acquired sensory neuronopathies. Distinguishing between acquired and genetic causes is nevertheless essential, as the prognoses are very different and treatment must be initiated rapidly in acquired forms. Clinical evaluation alone is often insufficient to differentiate these etiologies due to substantial overlap between presentations.

The objective of this study is to compare nerve ultrasound findings in a retrospective, multicenter cohort of patients with sensory neuronopathies of either genetic or acquired origin. The study also aims to analyze correlations between nerve caliber, clinical severity, disease duration, and electrophysiological parameters. Ultimately, this research seeks to determine whether the pattern of nerve atrophy observed on ultrasound is specific to genetic causes or may also be present in acquired forms.

• Study Type: Observational
• Enrollment (Estimated): 50

Contacts and Locations

• Study Contact: Name: Guillaume FARGEOT, MD; Phone Number: 00 33 1 42 21 60 02; Email: guillaume.fargeot@aphp.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adult patients diagnosed with sensory neuronopathy according to Camdessanché criteria, who underwent nerve ultrasound as part of routine clinical care. Patients are retrospectively identified from medical records across four French tertiary neurology centers between 2024 and 2025, including both acquired and genetic etiologies.

Description

Inclusion Criteria:

• Sensory ganglionopathy diagnosed according to the criteria of Camdessanché et al.
• Nerve ultrasound performed as part of routine clinical care.
• Age > 18 years.

Exclusion Criteria:

• Comorbid conditions that may interfere with the interpretation of sensory ganglionopathy.
• Lack of consent (patient opposition to the use of clinical data for research).

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cross-sectional area of peripheral nerves according to ganglionopathy etiology (genetic vs acquired)	Measurement of the cross-sectional area (mm²) of peripheral nerves on ultrasound (median nerve at forearm and arm, ulnar nerve at forearm and arm, sural nerve at ankle, radial sensory nerve at distal forearm, C5 and C6 roots at foraminal emergence, and vagus nerve at mid-cervical level) to compare nerve caliber between patients with genetic versus acquired sensory ganglionopathies	Baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between nerve cross-sectional area and clinical severity	Assessment of the association between peripheral nerve cross-sectional area (mm²) and clinical variables, including duration of symptoms (months) and severity of proprioceptive ataxia (Mariette score, 0-3)	Baseline
Correlation between nerve cross-sectional area and electrophysiological severity	Assessment of the association between peripheral nerve cross-sectional area (mm²) and electrophysiological parameters, including sensory nerve action potential amplitudes (sural and radial nerves, µV) and other available electrophysiological measures relevant to axonal loss	Baseline

Collaborators and Investigators

• Sponsor: Assistance Publique - Hôpitaux de Paris
• Investigators: Principal Investigator: Guillaume FARGEOT, MD, Assistance Publique - Hopitaux de Paris

Study record dates

Study Major Dates

• Study Start (Estimated): January 1, 2026
• Primary Completion (Estimated): January 1, 2026
• Study Completion (Estimated): January 1, 2027

Study Registration Dates

• First Submitted: January 9, 2026
• First Submitted That Met QC Criteria: January 19, 2026
• First Posted (Actual): January 26, 2026

Study Record Updates

• Last Update Posted (Actual): January 26, 2026
• Last Update Submitted That Met QC Criteria: January 19, 2026
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: CANVAS; Nerve ultrasound; sensory neuronopathy; ganglionopathy
• Other Study ID Numbers: APHP251638

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No