Charcot-Marie-tooth disease

Novel Myelin Protein Zero Mutation in 3 Generations of Vermonters With Demyelinating Charcot-Marie-Tooth Disease

OBJECTIVES

We report the clinical phenotype in 3 consecutive generations with demyelinating Charcot-Marie-Tooth disease that possess a novel sequence variant of myelin protein zero (MPZ).

METHODS

Family members from 3 consecutive generations were interviewed, examined, and studied with electrodiagnostic testing. Commercially available next-generation sequencing was performed for the proband. Single-gene analysis was performed for the remaining family members.

RESULTS

All patients demonstrated symmetric distal weakness; symmetric distal sensory loss; and diminished deep tendon reflexes. Electrodiagnostic testing was consistent with primary distal demyelination with secondary axon loss. Genetic testing identified a novel base-pair substitution of MPZ (c.314C>T), resulting in a missense variant (p.Pro105Leu).

CONCLUSIONS

The novel MPZ base-pair substitution in this family is associated with inherited distal demyelinating neuropathy and should be reclassified as pathogenic for Charcot-Marie-Tooth.

Evaluation of muscle strength and manual dexterity in patients with Charcot-Marie-Tooth disease

STUDY DESIGN

Matched pair study.

INTRODUCTION

Differences in hand-muscle strength/dexterity between dominant (DH) and non-dominant (NDH) hand in Charcot-Marie-Tooth disease (CMT) are not well understood.

PURPOSE OF THE STUDY

To compare muscle strength/dexterity between DH and NDH and to correlate manual dexterity, strength and sensory function.

PATIENTS AND METHODS

Thirty CMT patients were studied using functional muscle testing (FMT) and strength (dynamometry), dexterity (the Nine Hole Peg Test [NHPT]), and Jebsen-Taylor Hand Function [JTT]), and sensory function (the Nottingham Sensory Assessment [NSA]).

RESULTS

Scores were worse for DH than NDH on FMT (p = 0.043) and NHPT (p = 0.014) but not on JTT (p = 0.098), handgrip strength (p = 0.710) or tripod pinch (p = 0.645). NSA did not correlate significantly with any tests (p's0.05).

CONCLUSIONS

In CMT disease, DH appears more impaired than NDH in terms of function and dexterity. Greater muscle weakness in DH may also emerge as CMT progresses.

LEVEL OF EVIDENCE

3b.

Cavus foot reconstruction in 3 patients with Charcot-Marie-Tooth disease

Charcot-Marie-Tooth (CMT) is a progressive genetic disorder that produces motor and sensory neuropathy that affects the legs, feet, and hands. A dorsally based closing wedge midfoot osteotomy at the apex of the cavus foot deformity combined with soft tissue and other osseous procedures are procedures performed for CMT patients at The Western Pennsylvania Hospital. The focus of this article is to present a prospective evaluation of 3 patients using radiographic assessment, static biomechanical and the malleolar valgus index (MVI), dynamic alignment, and function results using the F-scan. These results demonstrate that patients have improved function with a plantigrade foot and decreased pain. The Short Form McGill Pain Questionnaire (SF-MPQ) showed that there was a decrease in pain. There was a decrease in the MVI and improved function comparing the preoperative and postoperative F-scan in all patients. The midfoot osteotomy addresses the apex of the progressive cavus foot deformity and provides a plantigrade foot in 3 CMT patients.

LEVEL OF CLINICAL EVIDENCE

4.

Spinal deformities in hereditary motor and sensory neuropathy: a retrospective qualitative, quantitative, genotypical, and familial analysis of 175 patients

STUDY DESIGN

Retrospective study of 175 patients with hereditary motor and sensory neuropathy (HMSN), i.e., Charcot-Marie-Tooth (CMT) disease.

OBJECTIVE

To investigate the frequency, age of onset, character, familial, and genotypical incidence of spinal deformities among HMSN patients.

SUMMARY OF BACKGROUND DATA

Prior studies addressing HMSN discuss the associated spinal deformities. However, these data vary significantly while inconsistently including genotypes within the classification framework.

METHODS

Plain-film radiographic spine studies of 175 HMSN patients were performed to determine the incidence, character, and severity of spinal deformity. The degree of the spinal deformity was evaluated measuring Cobb's angle of the main curve. The results of the entire cohort were initially assessed before being classified by genotype.

RESULTS

The incidence of spinal deformity for the entire group was 26%. Of these, 58% demonstrated scoliosis, 31% had kyphoscoliosis, and 11% had thoracic hyperkyphosis; 73% of patients with spinal deformity were classified as HMSN Type I with confirmed duplication of the PMP 22 (peripheral myelin protein) gene on chromosome 17. The incidence of spinal deformity by genotype was: duplication of the PMP 22 gene: 29% (25 of 87); deletion of the PMP 22 gene: 0% (0 of 15); Cx32 (connexin 32) gene mutation: 24% (8 of 34); and MPZ (myelin protein zero) gene mutation: 100% (6 of 6). Familial incidence of spinal deformity was found in "MPZ gene mutation" and "duplication of PMP 22 gene" subgroups.

CONCLUSION

This study demonstrates a 26% incidence of spinal deformity among HMSN patients. Spinal deformity was most frequently observed in patients with the MPZ gene mutation, where the most common familial incidence was also found.

Charcot-Marie-Tooth syndrome and surgical management for left main coronary artery disease

A 36-year-old male had coronary heart disease with a 12-year history of muscular weakness in his bilateral lower extremities and gait disturbance characterized by classical features of gastrocnemius and peroneal muscular atrophy. This is a clinical report of the first case of Charcot-Marie-Tooth disease (type 2) associated with the left main coronary artery disease requiring bypass surgery with cardiopulmonary bypass. The surgical procedure and postoperative course were uneventful. The patient was followed for 18 months postoperatively.

Hereditary motor and sensory neuropathy type VI with optic atrophy

PURPOSE

To present the detailed clinical findings of a large family with hereditary motor and sensory neuropathy type VI (HMSN VI), a syndrome featuring optic atrophy.

DESIGN

Observational case series.

METHODS

A detailed history was obtained and physical examination was made of the extended family of the proband for evidence of neurologic dysfunction. The OPA1 gene was screened for mutations by direct DNA sequencing.

RESULTS

Twelve of 97 family members examined are affected with signs of HMSN VI. Three other members have either optic atrophy or peripheral neuropathy, thus allowing an appreciation of the full clinical spectrum of disease. No mutations were found in the OPA1 gene.

CONCLUSIONS

This family demonstrates the variable expressivity of this disorder as well as incomplete penetrance. This is the largest known family with HMSN VI. No association was found with changes in the OPA1 gene.