Cranial nerve involvement in Charcot–Marie–Tooth Disease

BackgroundCharcot–Marie–Tooth Disease (CMT) is a rare disorder with less than 200,000 cases reported in the US every year, making diagnosis challenging. MR and CT imaging has become more common in the evaluation of CMT to identify areas of disease involvement.Case reportA 27-year-old female from Guatemala with a past history of polio initially presented to the emergency room for necrotizing pneumonia.MRI images demonstrated smoothly enlarged, mildly enhancing trigeminal nerves. CT showed bony widening of the skull base foramina. The patient was noted to have atrophy and weakness of her extremities with decreased sensation, distal more than proximal, and pes cavus. An electromyogram demonstrated absent response in the right median, ulnar, peroneal, and tibial motor studies and bilateral radial and right sural sensory studies. MRI of the spine demonstrated smooth, symmetric enlargement and mild enhancement of the distal spinal nerve roots and cauda equine.DiscussionCMT is a group of disorders with a wide range of clinical presentations and abnormalities. Cranial nerve involvement is infrequently described in CMT 1A. In our case and prior studies, there does not appear to be a correlation between cranial nerve involvement and symptoms. Trigeminal neuralgia has been described in patients in CMT, but is not common and was not seen in our patient despite abnormal trigeminal nerve findings on imaging. Our patient also demonstrated involvement of the facial nerve without facial muscle weakness. Clinical features are key in distinguishing CMT 1A from other forms of HMSN.     

Anticipation in a unique family with Charcot‐Marie‐Tooth syndrome and deafness: Delineation of the clinical features and review of the literature

Charcot‐Marie‐Tooth disease (CMT) is a clinically and genetically heterogeneous group of polyneuropathies characterized by degeneration of peripheral nerves, resulting in distal muscle atrophy, sensory loss, and deformities of hands and feet. We have studied 34 individuals in a large 84‐member four‐generation central Illinois family with autosomal dominant Charcot‐Marie‐Tooth and deafness. Nerve conduction velocities are consistent with type 1 CMT. Audiological evaluation revealed both auditory neuropathy and cochlear involvement in affected individuals. There is increasing clinical severity and younger age of onset of CMT and deafness with each progressive generation, suggestive of anticipation (P < 0.05). The proband, a female diagnosed at birth with hypotonia, bilateral vocal cord palsy, swallowing incoordination, and hearing impairment, died at age 18 months. Another individual died at the age of 3 months from hypotonia later attributed to CMT. Genetic analysis indicated that affected individuals in this family do not have the common 1.4 Mb duplication associated with type 1A CMT; however, all affected individuals have a unique G to C transversion at position 248 in coding exon 3 of the peripheral myelin PMP22 gene located on chromosome 17p11.2‐p12. This mutation is predicted to cause an Ala67Pro substitution in the second transmembrane domain of PMP22, consistent with the molecular cause of the CMT phenotype. However, it does not explain the cochlear component of the deafness, the clinical observation of anticipation, and other features in this family. © 2002 Wiley‐Liss, Inc.     

Clinical,electrophysiological, and molecular findings in early onset hereditary neuropathy with liability to pressure palsy

Introduction: The first episode of hereditary neuropathy with liability to pressure palsy (HNPP) in childhood is rare. Methods: We analyzed retrospectively the data of 7 patients with a deletion in PMP22 and onset of symptoms before age 18 years. Direct sequencing of the LITAF (lipopolysaccharide‐induced tumor necrosis factor) gene was performed in patients and family members. Results: Clinical presentations varied from mononeuropathies to brachial plexopathy, with recurrent episodes in 4 patients. Electrophysiological abnormalities characteristic for HNNP were found in most subjects. Analysis of the LITAF gene revealed an Ile92Val polymorphism in 6 of 7 (86%) probands and 5 of 7 (83%) family members, over 4 times greater frequency than in the general population. Conclusions: Clinical suspicion of HNPP even when nerve conduction study results do not fulfill HNPP criteria should indicate genetic testing. In our patients, early‐onset HNPP was associated frequently with isoleucine92valine LITAF polymorphism. Muscle Nerve 50: 914–918, 2014     

中西医结合治疗Marie共济失调

目的：探讨Marie共济失调的中西医结合治疗方法和思路。方法：对确诊为Marie共济失调的5例患者，运用滋阴补肾方剂和头皮针结合复方氨基酸等治疗，并分级记分进行治疗前后的评分对比。结果：5例中4例不同程度改善，评分积极分均有减少。结论：运用中西医结合治疗Marie共济失调有一定疗效，为本病治疗提出了一条新的思路。     

Clinical and biochemical markers in CIPN: A reappraisal

The increased survival of cancer patients has raised growing public health concern on associated long-term consequences of antineoplastic treatment. Chemotherapy-induced peripheral neuropathy (CIPN) is a primarily sensory polyneuropathy, which may be accompanied by pain, autonomic disturbances, and motor deficit. About 70% of treated cancer patients might develop CIPN during or after the completion of chemotherapy, and in most of them such complication persists after six months from the treatment. The definition of the potential risk of development and resolution of CIPN according to a clinical and biochemical profile would be certainly fundamental to tailor chemotherapy regimen and dosage on individual susceptibility. In recent years, patient-reported and clinician-related tools along with quality of life instruments have been featured as primary outcomes in clinical setting and randomized trials. New studies on metabolomics markers are further pursuing accurate and easily accessible indicators of peripheral nerve damage. The aim of this review is to outline the strengths and pitfalls of current knowledge on CIPN, and to provide a framework for future potential developments of standardized protocols involving clinical and biochemical markers for CIPN assessment and monitoring.     

Phenotype expression in women with CMT1X

Charcot-Marie-Tooth disease type 1X (CMT1X) is the second most common inherited peripheral neuropathy. Women with CMT1X typically have a less severe phenotype than men, perhaps because of X-inactivation patterns. Our objective was to determine the phenotype of women with CMT1X and whether X-inactivation patterns in white blood cells (WBCs) differ between females with CMT1X and controls. Thirty-one women with CMT1X were evaluated using the CMT neuropathy score (CMTNS) and the CMT symptom score in cross-sectional and longitudinal analyses. Lower scores correspond to less disability. WBCs were analyzed for X-inactivation pattern by androgen receptor X-inactivation assay in 14 patients and 23 controls. The 31 women's mean CMTNS was 8.35. Two-thirds of the cohort had a mild CMTNS (mean 4.85) and one-third had a moderate CMTNS (mean 14.73). Three patients had a CMTNS of 0. The pattern of X-inactivation did not differ between the affected and control groups. Women with CMT1X presented with variable impairment independent of age, type of mutation, or location of mutation. No evidence supported the presence of a gap junction beta-1 (GJB1) mutation affecting the pattern of X-inactivation in blood. Further studies are planned to determine whether X-inactivation is the mechanism for CMT1X females' variable phenotypes.     

Distal hereditary motor neuropathy

Introduction

Distal hereditary motor neuropathy (dHMN), also known as spinal muscular atrophy, represents a group of clinically and genetically heterogeneous diseases caused by degenerations of spinal motor neurons and leading to distal muscle weakness and wasting. Nerve conduction studies reveal a pure motor axonopathy and needle examination shows chronic denervation.

State of art

dHMN were initially subdivided into seven subtypes according to mode of inheritance, age at onset, and clinical evolution. Recent studies have shown that these subtypes are still heterogeneous at the molecular genetic level and novel clinical and genetic entities have been characterized. To date, mutations in 11 different genes have been identified for autosomal-dominant, autosomal-recessive, and X-linked recessive dHMN. Most of the genes encode protein involved in housekeeping functions, endosomal trafficking, axonal transport, translation synthesis, RNA processing, oxidative stress response and apoptosis.

Perspectives

The pathophysiological mechanisms underlying dHMN seem to be related to the “length-dependent” death of motor neurons of the anterior horn of the spinal cord, likely because their large axons have higher metabolic requirements for maintenance.

Conclusion

dHMN remain heterogeneous at the clinical and molecular genetic level. The molecular pathomechanisms explaining why mutations in these ubiquitously expressed housekeeping genes result in the selective involvement of spinal motor neurons remain to be unravelled.