Abstract Details

Title Preserved Reflexes and Partial Conduction-Block in CMT1C

Topic Peripheral Nerve

Presentation(s) P07 - (-)

Poster/Presentation
Number 058

Objective

Background BACKGROUND: Charcot-Marie-Tooth, type 1 (CMT1) is an inherited disorder resulting in diffuse demyelination of peripheral axons. The severity of symptoms is variable, however most patients present with deformities of the feet, absent muscle stretch reflexes and reduced sensation in a stocking-glove pattern. Mutations in the LITAF (Lipopolysaccharide-induced tumor necrosis factor-alpha factor) gene, CMT1C, account for less than 1% of CMT1. These patients are not typically described as phenotypically distinct from other CMT1 subtypes on examination. Partial conduction-block on EMG has been described in this population.

Design/Methods DESIGN/METHODS: Case Report.

Results RESULTS: A 58-year-old woman of Polish and Russian descent presented with severe pes cavus, hammer toes and impaired balance since childhood. Her mother had similar symptoms. The patient's examination was significant for her foot deformities, mild sensory loss in the feet and mild weakness of toe extension bilaterally. Her reflexes were normal (2+) throughout, including her ankles. Multiple EMGs over several years demonstrated uniformly slowed conduction velocities; however, partial conduction-block was noted in multiple nerves. A superimposed acquired demyelinating neuropathy was thought unlikely given the lack of acute/subacute symptom progression. Serum B12 level, SPEP/immunofixation were unremarkable. An EMG of the patient's mother demonstrated similar slowing of conduction velocities without conduction-block. Previous gene testing including PMP 22 duplication/deletion/sequencing, CX-32, MPZ,EGR-2 and NF-L sequencing was negative. LITAF gene testing, sent based upon her history and presence of conduction-block in an apparently inherited neuropathy, revealed a pathogenic mutation. (G to A, nucleotide position 334, codon 112, amino acid change glycine to serine).

Conclusions CONCLUSIONS: Preserved reflexes may be seen CMT1C. Partial conduction-block in the setting of an inherited demyelinating neuropathy should prompt consideration of LITAF gene mutations.

Authors/Disclosures
Colin Quinn, MD (University of Pennsylvania) PRESENTER	Dr. Quinn has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Sanofi. Dr. Quinn has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Abcuro. Dr. Quinn has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Voyager Therapeutics. Dr. Quinn has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Catalyst Pharmaceuticals.
Johnny Salameh, MD, FAAN	Dr. Salameh has nothing to disclose.
Milena Pavlova, MD (Brigham and Womens Hospital Dept of Neurology)	Dr. Pavlova has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Pear Therapeutics. Dr. Pavlova has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Oakstone. The institution of Dr. Pavlova has received research support from Jazz. The institution of Dr. Pavlova has received research support from Vanda. The institution of Dr. Pavlova has received research support from Biomobie. Dr. Pavlova has received personal compensation in the range of $500-$4,999 for serving as a Didactic article with Neurodiem.

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