Overview

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.

Eligibility

Inclusion criteria:

• collaborative children, adolescents and young adults aged 10-30 years
• genetic diagnosis of CMT1A, or clinical diagnosis and genetic diagnosis in affected relatives
• able to walk with/ without support.

Exclusion Criteria:

• neuromuscular disorders other than CMT1A
• concomitant disease preventing correct patient evaluation and contraindication to qMRI