Abstract
Objective The SCN11A gene encodes the NaV1.9 sodium channel found exclusively in peripheral nociceptive neurons.
Methods All enrolled participants were evaluated clinically by electrophysiologic studies, DNA sequencing, and punch skin biopsies.
Results All affected family members are afflicted by episodes of pain. Pain was predominantly nociceptive, but not neuropathic in nature, which led a diagnosis of fibromyalgia in some patients. All patients had normal findings in nerve conduction studies for detecting large nerve fiber neuropathies and skin biopsies for detecting small nerve fiber pathology.
Conclusions Unlike those patients with missense mutations in SCN11A, small fiber sensory neuropathy, and neuropathic pain, the Arg225Cys SCN11A in the present study causes predominantly nociceptive pain with minimal features of neuropathic pain and undetectable pathophysiologic changes of peripheral neuropathy. This finding is consistent with dysfunction of nociceptive neurons. In addition, since nociceptive pain in patients has led to the diagnosis of fibromyalgia, this justifies a future search of mutations of SCN11A in patients with additional pain phenotypes such as fibromyalgia to expand the clinical spectrum beyond painful small fiber sensory neuropathy.
Glossary
- ALS=
- amyotrophic lateral sclerosis;
- CMT=
- Charcot-Marie-Tooth;
- CMTES=
- CMT Examination Score;
- CMTNS=
- CMT neuropathy score;
- DP=
- diabetic polyneuropathy;
- EPS=
- episodic pain syndrome;
- IRB=
- institutional review board;
- NCS=
- nerve conduction study;
- RAPS=
- Rheumatoid Arthritis Pain Scale
Footnotes
Funding information and disclosures are provided at the end of the article. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/NG.
The Article Processing Charge was funded by NIH grant.
- Received February 14, 2018.
- Accepted in final form May 21, 2018.
- Copyright © 2018 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.
This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND), which permits downloading and sharing the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.
Letters: Rapid online correspondence
NOTE: All contributors' disclosures must be entered and current in our database before comments can be posted. Enter and update disclosures at http://submit.ng.neurology.org. Exception: replies to comments concerning an article you originally authored do not require updated disclosures.
- Stay timely. Submit only on articles published within the last 8 weeks.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- 200 words maximum.
- 5 references maximum. Reference 1 must be the article on which you are commenting.
- 5 authors maximum. Exception: replies can include all original authors of the article.
- Submitted comments are subject to editing and editor review prior to posting.