MFN2 mutations cause severe phenotypes in most patients with CMT2A
S M E Feely1, M Laura, C E Siskind
1Department of Neurology, Wayne State University, 421 Ea Canfield, Detroit, MI 48201, USA.
Neurology
|April 22, 2011
Summary
Mutations in the mitofusin 2 gene (MFN2) cause Charcot-Marie-Tooth disease type 2A (CMT2A), often leading to severe, early-onset neuropathy, primarily affecting motor function and proprioception.
Area of Science:
- Genetics
- Neurology
- Mitochondrial Biology
Background:
- Charcot-Marie-Tooth disease type 2A (CMT2A) is the most common form of CMT2.
- It stems from mutations in the mitofusin 2 gene (MFN2), crucial for mitochondrial fusion and ER-mitochondria tethering.
- Existing CMT2A phenotypes show wide variability in severity.
Purpose of the Study:
- To investigate the prevalence and clinical characteristics of CMT2A.
- To correlate MFN2 mutations with disease severity and specific neurological deficits.
Main Methods:
- Genetic testing was performed on 99 CMT2 patients from Wayne State University and 27 from the National Hospital for Neurology and Neurosurgery.
- A cross-sectional analysis was conducted on patients diagnosed with CMT2A.
Main Results:
- MFN2 mutations were identified in 21% of CMT2 patients.
- CMT2A patients exhibited earlier onset and more severe impairment compared to non-CMT2A patients.
- Twenty-three of 27 CMT2A patients were nonambulatory before age 20; 11 had pure motor neuropathy, and 5 had additional proprioception loss.
Conclusions:
- MFN2 mutations are strongly associated with severe neuropathy, often presenting as a primary motor deficit or with significant proprioception loss.
- Disruptions in MFN2's functional domains are particularly implicated in causing neuropathy.
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