CMT

Tremor is a symptom that has already been described in many case reports and case series concerning patients with Charcot-Marie-Tooth (CMT) disease. However, the pathophysiology of tremor in this condition remains largely unclear. It has also not been sufficiently investigated to what extent tremor in CMT patients constitutes a relevant impairment of quality of life. This project focuses on a more detailed characterization of tremor in CMT patients using surface electromyography and accelerometer analysis, as well as the collection of individual clinical data, particularly regarding the symptom of tremor, in order to facilitate the characterization and etiological classification of the tremor. In addition, a questionnaire-based assessment will be conducted to capture the impact of tremor on activities of daily living and the associated burden in this specific patient cohort. The entire data collection process will be supported by a clinical examination, which will be video-recorded by experienced neurologists to ensure more reliable analysis. This serves both the characterization of tremor and the illustration of its functional limitations. Where available, the data will be correlated with genetic variants to allow conclusions about possible genetic predispositions or disease progression. As a control group, CMT patients who have not yet reported a tremor will be included.

The most common inherited neuropathy is Charcot-Marie-Tooth disease type 1A (CMT1A), caused by a duplication of the gene expressing PMP22. CMT1A patients develop symptoms in early childhood with variable progression and there is no established therapy until now. Therapy must start in childhood, before peripheral nerves degenerate. However, the investigators lack easily obtainable biomarkers in early disease stages. In peripheral nerves from young CMT1A rats, the invstigators found changes in gene regulation that predicted the clinical disease severity later in adulthood, and gene expression from blood samples in young CMT1A rats were strong predictors of the future disease course. In blood samples from adult CMT1A patients, changes in gene expression also correlated with disease severity, demonstrating that findings can be "translated" from CMT rats to patients. Objectives: In CMT-MODs, the investigators will identify disease and prognostic biomarkers in young CMT1A patients. Strategy/ Methodology: In a translational approach, the investigators will first perform a multi-omic analysis (transcriptomic and proteomic) in sciatic nerves, blood and skin of young CMT1A rats at two timepoints in order to identify novel early markers of disease severity. In parallel, the investigators will assess a large cohort of CMT1A children, adolescents and young adults aged 10-30 years over 12 months applying the novel clinical outcome measures CMT Examination Score/CMT Neuropathy Score Version Version 2 Rasch versions (CMTES-R/CMTNSv2-R), the functional outcome measure CMT-FOM, pCMT-Qol, as well as a nerve conduction study (NCS) and quantitative MRI. Moreover, the following patient-reported outcome measures (PROMs) will also applied: VAS (pain, fatigue, cramps), WALK-12 and PGI-c. Blood (and optional skin) samples will be taken and gene expression of the most promising candidates, which the investigators originally identified in CMT rats, will be measured. Results: This unprecedented assessment of CMT patients and animal models at early disease stages will allow CMT-MODs to establish biomarkers that may serve as a standard readout for disease severity and predict the disease course. Impact: These novel diagnostic measures are urgently needed and will make clinical trials in early disease stages (children) possible in order to effectively treat and prevent CMT1A disease. Without effective biomarkers, promising preclinical therapeutic strategies cannot be translated to patients.

The Myelin Disorders Biorepository Project (MDBP) seeks to collect and analyze clinical data and biological samples from leukodystrophy patients worldwide to support ongoing and future research projects. The MDBP is one of the world's largest leukodystrophy biorepositories, having enrolled nearly 2,000 affected individuals since it was launched over a decade ago. Researchers working in the biorepository hope to use these materials to uncover new genetic etiologies for various leukodystrophies, develop biomarkers for use in future clinical trials, and better understand the natural history of these disorders. The knowledge gained from these efforts may help improve the diagnostic tools and treatment options available to patients in the future.