Early Detection of Neuropathy in ATTRv

Study Overview
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Brief Summary
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The purpose of the study is to evaluate and compare different tools that are used to detect evidence of peripheral neuropathy in patients with TTRv.

Detailed Description
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Early detection of peripheral neuropathy in patients with TTRv is important to support initiation of therapy that alters the course of the disease. Current tools used to detect peripheral neuropathy may not be sensitive, especially in very early and distal peripheral neuropathy. This study will compare different methods of assessing for peripheral neuropathy including using in-vivo reflectance confocal microscopy to assess for meissner corpuscles, serum neurofilament light chain, quantitative sensory testing, neuropathy impairement scores, nerve conduction studies and quality of life and symptoms questionnaires.

Official Title
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Early Detection of Peripheral Neuropathy in Hereditary Transthyretin Amyloidosis

Conditions
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Hereditary Amyloidosis, Transthyretin-Related

Intervention / Treatment
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* Diagnostic Test: neurofilament light chain
* Diagnostic Test: In-vivo Meissner Corpuscle imaging
* Diagnostic Test: Nerve conduction study


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 30 years or older Patients with known TTR mutations and neuropathy, patients with TTR mutation and no symptoms within less than 10 years of typical onset of disease., or healthy persons without neuropathy Exclusion Criteria: Patients with neuropathy other than TTR amyloid Subjects with risk factors for neuropathy (diabetes, history of neuropathy in the family, neurotoxic drugs) or with neurological disorder associated with elevated NFL The following distribution of age ranges will be considered when enrolling healthy participants: 5 patients age 30-40 5 patients age 40-50 5 patients age 50-60 5 patients age 60-70 The following age limitations will be in place for asymptomatic TTR carriers. The idea is to select patients that are likely to develop evidence of disease within the next 10 years. Non V122I mutation> or =30 V122I> or = 55

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Symptomatic TTRv<br>Patients with known TTR mutations and neuropathy | Diagnostic Test: neurofilament light chain<br>* Blood test<br>Diagnostic Test: In-vivo Meissner Corpuscle imaging<br>* Imaging<br>Diagnostic Test: Nerve conduction study<br>* Nerve conduction study<br>|
| Asymptomatic TTRv<br>Patients with TTR mutation and no symptoms within less than 10 years of typical onset of disease | Diagnostic Test: neurofilament light chain<br>* Blood test<br>Diagnostic Test: In-vivo Meissner Corpuscle imaging<br>* Imaging<br>Diagnostic Test: Nerve conduction study<br>* Nerve conduction study<br>|
| Healthy controls<br>Age and sex matched healthy controls without neuropathy or other neurological disorder. | Diagnostic Test: neurofilament light chain<br>* Blood test<br>Diagnostic Test: In-vivo Meissner Corpuscle imaging<br>* Imaging<br>Diagnostic Test: Nerve conduction study<br>* Nerve conduction study<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Serum neurofilament light chain | Change in sesrum neurofilament light chain concentration at 12 months | 12 months | 
| Meissner corpuscles | Change in Meissner corpuscles density at 12 months | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quantitative sensory testing | Testing of vibratory sensation using a tuning fork, testing of light touch using neurofilament | 12 months | 
| Neuropathy symptoms questionnaire | Questionnaire that assess symptoms of neuropathy and severity. | 12 months | 
| Neuropathy impairment score | Neurological examination reporting motor strength, reflexes and sensation. Scale ranges from 0 (normal) to 244, with a higher score indicating greater impairment. | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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transthryretin, Hereditary transthyretin amyloidosis, TTRv, familial amyloid polyneuropathy