Peripheral Myelin Protein 22 gene duplication with atypical presentations: A new example of the wide spectrum of Charcot-Marie-Tooth 1A disease

Mathis, Stéphane; Corcia, Philippe; Tazir, Mériem; Camu, William; Magdelaine, Corinne; Latour, Philippe; Biberon, Julien; Guennoc, Anne‐Marie; Richard, Laurence; Magy, Laurent; Funalot, Benoît; Vallat, Jean‐Michel

doi:10.1016/j.nmd.2014.03.014

Cited by 19 publications

(29 citation statements)

References 19 publications

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“…In our study CB was found in 25% of children with CMT1a. CB in CMT1a has also been reported by other authors (Oh and Chang , ; De Angelis et al, ; Houlden et al, ; Mathis et al, ; Vill et al, ) . AMNS and a 10 m/s CV difference abnormality indicates patchy demyelination.…”

Section: Discussionsupporting

confidence: 81%

Are electrophysiological criteria useful in distinguishing childhood demyelinating neuropathies?

Potulska‐Chromik

Ryniewicz

Aragon-Gawinska

et al. 2016

J Peripheral Nervous Sys

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Childhood chronic inflammatory demyelinating polyneuropathy (CIDP) needs to be differentiated from hereditary neuropathy. We aimed to validate existing CIDP nerve conduction study (NCS) criteria in a group of children with demyelinating neuropathies of chronic or subacute onset. Retrospective analysis of clinical and NCS results in 18 children with CIDP, 7 with hereditary neuropathy with pressure palsy (HNPP), and 24 with Charcot-Marie-Tooth 1a (CMT1a). AAN and EFNS electrodiagnostic CIDP criteria were fulfilled in 17 of 18 CIDP, 3 of 7 HNPP, and 23 of 24 CMT1a patients. A distal compound muscle action potential (dCMAP) of >9 ms was observed in 14 of 18 CIDP patients but not in any patients with HNPP. Abnormal median/normal sural SNAP (AMNS) and a 10 m/s difference between conduction velocities (CV) of two corresponding nerves were not observed in any CMT1a patients. NCS in CMT1a, HNPP, and CIDP reflect demyelination. dCMAP duration, sensory AMNS, and a 10 m/s CV difference parameter are most useful in the differential diagnosis of pediatric CIDP.

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Section: Discussionsupporting

confidence: 81%

Are electrophysiological criteria useful in distinguishing childhood demyelinating neuropathies?

Potulska‐Chromik

Ryniewicz

Aragon-Gawinska

et al. 2016

J Peripheral Nervous Sys

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“…However, genotype–phenotype correlations are not so obvious in PMP22‐related CMT. In fact, besides different degrees of disease severity [Birouk et al., ], also variable phenotypes, including HNPP‐like and CMT2‐like, were described in CMT1A [Thomas et al., ; Bergamin et al., ; Mathis et al., ]. Finally, in a subpopulation of CMT1A patients, a genetic triplication causing a more severe phenotype was also found [Liu et al., ].…”

Section: Discussionmentioning

confidence: 99%

Alternative Splicing in the HumanPMP22Gene: Implications in CMT1A Neuropathy

et al. 2015

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CMT1A patients commonly share PMP22 genetic overloading but they show phenotypic heterogeneity and variability in PMP22 mRNA and protein expression. Moreover, PMP22 mRNA levels do not correlate with clinical outcome measures in these patients, suggesting their uselessness as a disease biomarker. Thus, in-depth analysis of PMP22 transcription and translation might help to define its pathogenic role in CMT1A. We focused on the alternative splicing of PMP22 gene to verify whether mRNA processing is altered in CMT1A. We identified three new PMP22 transcripts enriched in human sural nerve biopsies. One of them was an untranslated variant, whereas the other two originated from a PMP22 undescribed exon and encoded for a new putative protein localized in the endoplasmic reticulum. As splicing events in the PMP22 gene are differently regulated in tissues and during development, we analyzed the levels of PMP22 transcripts and their splicing pattern in human and experimental CMT1A. We found an altered PMP22 splicing ratio in the CMT1A rat. In addition, we showed a remarkable derangement in rat QKI expression, which is a critical regulator of splicing during myelination. Overall, our data suggest that an alteration of mRNA processing could be a pathogenic mechanism in CMT1A.

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“…This finding suggests that in the present patient, acquired immune‐mediated neuropathy could mainly produce conduction blocks. In contrast, hereditary neuropathy with liability to pressure palsies‐like conduction block could also overlap with CMT1A . However, there was no episode of nerve compression, and the efficacy of IVIG for muscle weakness and negative conversion of GM1 antibody suggested that overlapping CIDP with CMT1A was more probable in our patient.…”

Section: Discussionmentioning

confidence: 57%

Coexistence of Charcot–Marie–Tooth disease type 1A and chronic inflammatory demyelinating polyradiculoneuropathy with conduction blocks

Shimizu

Hanajima

Shimizu

et al. 2016

Neurology & Clinical Neurosc

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We present a 47-year-old woman with upper extremity muscle weakness and sensory disturbance during a slowly progressive course of leg muscle weakness. First, she was diagnosed with chronic inflammatory demyelinating polyradiculoneuropathy. However, with gene analysis of PMP22 duplication, she was diagnosed with Charcot-Marie-Tooth type 1A. In the electrophysiological study, nerve conduction blocks were shown, which is inconsistent with Charcot-Marie-Tooth type 1A. Intravenous immunoglobulin therapy improved both her symptoms and the conduction blocks. We suggest that inflammatory demyelinating polyradiculoneuropathy was associated with Charcot-Marie-Tooth type 1A in this patient. The presence of the conduction blocks could be a hallmark of the associating inflammatory demyelinating polyradiculoneuropathy. Intravenous immunoglobulin therapy might be partly effective in such patients.

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Peripheral Myelin Protein 22 gene duplication with atypical presentations: A new example of the wide spectrum of Charcot-Marie-Tooth 1A disease

Cited by 19 publications

References 19 publications

Are electrophysiological criteria useful in distinguishing childhood demyelinating neuropathies?

Are electrophysiological criteria useful in distinguishing childhood demyelinating neuropathies?

Alternative Splicing in the HumanPMP22Gene: Implications in CMT1A Neuropathy

Coexistence of Charcot–Marie–Tooth disease type 1A and chronic inflammatory demyelinating polyradiculoneuropathy with conduction blocks

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