Genotype/Phenotype Correlation of MORC2 Mutations

Deciphering MORC2 Genotype/Phenotype Correlation to Improve Patient Diagnostic

The Microrchidia CW-type zinc finger 2 (MORC2) gene encodes a protein expressed in all tissues and enriched in the brain. It is involved in Charcot-Marie-Tooth disease, with mire than 30 families presenting MORC2 mutations. Recently, MORC2 mutation have been shown to be responsible for more complex phenotypes like DIFGAN: developmental delay, impaired growth, dysmorphic facies and axonal neuropathy.

Different mutations are responsible from a diverse spectrum of phenotype, from CMT to DIFGAN.

MORC2 is involved, through its ATPase activity, in DNA repair, chromatin remodeling and epigenetic silencing via the Human silencing hub (HUSH) complex. Our hypothesis is that the hypo- or hyper-activation of the HUSH complex by different MORC2 mutations could be responsible for different phenotypes in patients. The aim of this study is to perform a genotype-phenotype correlation study in patients presenting MORC2 mutations.

Inclusion Criteria:

• Presence of a mutation in the MORC2 gene, identified during an evaluation for peripheral neuropathy or intellectual disability
• Patient has undergone electromyography (EMG) or is able to undergo EMG during the inclusion visit
• Affiliation with the national health insurance system
• Informed consent from the patient if an adult, or from parents/legal guardians if the patient is a minor

Exclusion Criteria:

• Presence of another mutation responsible for peripheral neuropathy or intellectual disability
• Refusal to undergo biological sample collection
• Regulatory exclusion criteria:
• Pregnant, postpartum, or breastfeeding women
• Individuals deprived of liberty by judicial or administrative decision
• Individuals not affiliated with a social security system or not benefiting from an equivalent health coverage scheme