This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
Abstract
Background: Axonal neuropathy linked to the CMT2A locus was originally associated with a mutation in the KIF1B gene. However, mutations in this gene have not been described associated with any other CMT2A families. Recently, mutations in the MFN2 gene, encoding the mitochondrial GTPase mitofusin 2 (Mfn2), have been identified as causative of CMT2A in seven families. The authors report three additional CMT2A families associated with novel mutations in highly conserved regions of the Mfn2 GTPase domain.
Methods: The authors performed a standardized neuromuscular and nerve conduction examination, genotyped known CMT loci, and analyzed the MFN2 gene by direct sequencing in three pedigrees and 10 additional probands affected by axonal CMT.
Results: Sequencing of the MFN2 gene revealed a novel mutation in each family (c.818T>G, c.638T>C, and c.314C>T). The largest family demonstrated an age-independent variable expression such that approximately one quarter of individuals with the mutation presented with features mild enough as to remain occult even with electrophysiologic evaluation.
Conclusion: These results confirm that the majority of cases of CMT linked to the CMT2A locus are due to MFN2 mutations. The phenotype is largely indistinguishable from KIF1B-related CMT and from CMT2E and CMT2F. At least in some families, as many as 25% of individuals with MFN2 mutations may be asymptomatic and have a normal electrophysiologic examination, although a detailed neuromuscular examination may suggest the trait. Given the frequency of MFN2 mutations among CMT2 probands (3/13, or 23%), genetic testing of CMT2 patients should begin with a screen of the MFN2 gene.
AAN Members
We have changed the login procedure to improve access between AAN.com and the Neurology journals. If you are experiencing issues, please log out of AAN.com and clear history and cookies. (For instructions by browser, please click the instruction pages below). After clearing, choose preferred Journal and select login for AAN Members. You will be redirected to a login page where you can log in with your AAN ID number and password. When you are returned to the Journal, your name should appear at the top right of the page.
AAN Non-Member Subscribers
Purchase access
Letters: Rapid online correspondence
REQUIREMENTS
You must ensure that your Disclosures have been updated within the previous six months. Please go to our Submission Site to add or update your Disclosure information.
Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.
If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.
Submission specifications:
- Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
- Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
- Submit only on articles published within 6 months of issue date.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- Submitted comments are subject to editing and editor review prior to posting.
