Abstract Details

Title HSPB1 c523C>T Mutation: Clinical and Electrophysiological Study of a Large CMT2F Family

Topic Peripheral Nerve

Presentation(s) P05 - (-)

Poster/Presentation
Number 070

Objective

Background BACKGROUND: The rare Charcot-Marie-Tooth disease type II F (CMT2F) is due to HSPB1 gene mutations, resulting in distal axonal sensory-motor neuropathy, but also in distal hereditary motor neuropathy (dHMN). The sensory involvement is usually minor.

Design/Methods DESIGN/METHODS: Thirteen members of a French family had both clinical and electromyography examination using a standard protocol. After identification of the proband's mutation, the family members were analyzed by direct sequencing of the exon 3.

Results RESULTS: Five members had heterozygous c523C>T HSPB1 mutation. The median age of onset was 38 years old (SD ± 7.42). Clinical evaluation revealed a distal motor and sensitive peripheral deficit, amyotrophy and areflexia, but no other associated sign. Ataxia was severe for the two oldest members. Electrophysiological examination showed a distal axonal sensori-motor neuropathy with chronic denervation signs. Mean CMAP amplitude was 1.7 mV for the peroneal nerve and 1.1 mV for the tibial nerve. Mean SNAP amplitude was 2.9 [micro]V for the sural nerve. It was absent in the two oldest members. The upper limbs were lately affected with purely motor abnormalities. There was an important intra-familial heterogeneity in the age of onset (from 30 to 50 years old), in the disease severity and in the sensory involvement (mild to severe). This heterogeneity could not be explained by the sole disease duration.

Conclusions CONCLUSIONS: The c523C>T mutation of HSPB1 gene had a double expression presenting both as a motor distal neuropathy and a sensory-motor neuropathy in this single family. Sensory involvement can be severe and increases the handicap, it is mainly correlated to disease duration, but other individual factors are likely to be involved.

Authors/Disclosures
Emmanuelle Folgoas PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
Hubert Le Noan	No disclosure on file
	No disclosure on file
	No disclosure on file
Yann Pereon, MD, PhD (Chu De Nantes)	No disclosure on file
Jean M. Schoenen, MD, PhD (Univ Depts of Neuroanatomy and Neuro)	No disclosure on file

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