Charcot-Marie-Tooth disease type 1C: Clinical and electrophysiological findings for the c.334G>a (p.Gly112Ser) Litaf/Simple mutation.
BACKGROUND
Charcot-Marie-Tooth disease type 1C (CMT1C) is a rare, dominantly inherited neuropathy caused by mutations in the lipopolysaccharide-induced tumor necrosis factor (LITAF) or small integral membrane protein of the lysosome/late endosome (SIMPLE) gene.


METHODS
We present a case series comprised of 10 patients in whom CMT1C is caused by a Gly112Ser substitution in the encoded protein. We focus on clinical presentation, electrodiagnostic analyses, and our findings in the context of previously described cases.


RESULTS
The Gly112Ser mutation causing CMT1C is a mild form of CMT, as patients walked on time, had less weakness than those with Charcot-Marie-Tooth disease type 1A (CMT1A), had a CMT neuropathy score (CMTNS) indicative of mild disease, and had faster ulnar and median motor nerve conduction velocities compared to those with CMT1A.


CONCLUSIONS
The G112S mutation in LITAF seems to be clinically indistinguishable from a mild presentation of CMT1A. Muscle Nerve 56: 1092-1095, 2017.
Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA.
Nivedita U
NU
Jerath
Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA.
Michael E
ME
Shy
D000293:Adolescent; D000328:Adult; D000368:Aged; D002607:Charcot-Marie-Tooth Disease / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D055724:Electrophysiological Phenomena / Q000502:physiology; D005260:Female; D005998:Glycine / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D012189:Retrospective Studies; D012694:Serine / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D055815:Young Adult
C118738:LITAF protein, human; D009687:Nuclear Proteins; D014157:Transcription Factors; D012694:Serine; D005998:Glycine
CMT1C; EDx; HMSN type 1; LITAF; SIMPLE; nerve conduction studies