Coexistence of two chronic neuropathies in a young child: Charcot–marie–tooth disease type 1A and chronic inflammatory demyelinating polyneuropathy

We report an 18‐month‐old Charcot–Marie–Tooth type 1A (CMT1A) patient who developed a rapid‐onset neuropathy, with proximal and distal weakness, and non‐uniform nerve conduction studies. The neuropathy responded well to immunomodulation, confirming the coexistence of an inherited and an inflammatory neuropathy. Unexpected clinical and/or electrophysiological manifestations in CMT1A patients should alert clinicians to concomitant inflammatory neuropathy. In addition, this association raises reflections about disease mechanism in CMT1A. Muscle Nerve, 2010     

Clinical correlates of charcot–marie–tooth disease in patients with pes cavus deformities

Introduction: Given its association with Charcot–Marie–Tooth disease (CMT), pes cavus is a common reason for referral to a neurologist. We investigated clinical features that may predict CMT in children with pes cavus. Methods: In this study we retrospectively reviewed pes cavus patients referred to Boston Children's Hospital in the past 20 years. Patients were categorized as idiopathic or CMT, based on EMG/genetic testing, and their clinical features were compared. Results: Of the 70 patients studied, 33 had idiopathic pes cavus, and 37 had genetically confirmed CMT. Symptoms of weakness, unsteady gait, family history of pes cavus and CMT, and signs of sensory deficits, distal atrophy and weakness, absent ankle jerks, and gait abnormalities were associated with CMT. Conclusions: In children with pes cavus, certain clinical features can predict CMT and assist in selection of patients for further, potentially uncomfortable (EMG) and expensive (genetic) confirmatory investigations. Muscle Nerve, 2013     

Pain and small fiber function in charcot–marie–tooth disease type 1A

Introduction: Charcot–Marie–Tooth (CMT) disease type 1A is the most common form of CMT. The main clinical features are distal weakness, sensory loss, and skeletal deformities. Although pain is a frequent complaint, small fiber involvement in CMT1A has not been studied extensively. Methods: We assessed pain and small fiber involvement in 49 CMT1A patients using a variety of pain scales, pain questionnaires, and thermal thresholds. Results: Forty‐three of 49 patients (88%) complained of pain. The pain was localized to the feet in 61% of patients. Only 18% of patients had neuropathic pain. Cold and warm detection thresholds were elevated in 53% and 12% of patients, respectively. Conclusions: Our findings confirm that CMT1A patients have significant pain, which is more likely to be multifactorial in origin and suggests that a proportion of patients have small fiber dysfunction affecting mainly thinly myelinated Aδ fibers. Muscle Nerve 50 : 366–371, 2014     

Normal nerve striations are altered in the trembler‐J mouse,a model of charcot–marie–tooth disease

Introduction: This study was initiated because it was noted that the peripheral nerves of Trembler‐J mice (a model of human Charcot–Marie–Tooth disease) appear to lack normal striations. Methods: We performed confocal microscopy of whole sciatic nerves and tested the effect of axial stress on impulse conduction. Results: We found that the axons of mutant mice were longer than those of the wild‐type (1.55 mm of axon/mm length of nerve vs. 1.28 mm/mm respectively). This axonal elongation altered the helical nerve striations (bands of Fontana). As nerves were stretched axially, the conduction distance became correspondingly shorter. The effect on latency was significantly greater in the more coiled nerves of Trembler‐J mice (P = 0.038). Conclusions: The finding that mice with a mutated peripheral myelin protein 22 (PMP22) possess excessively long axons may be related to the excess Schwann cell numbers found in this disorder. Muscle Nerve 51 : 246–252, 2015     

Four novel point mutations in the PMP22 gene with phenotypes of HNPP and Dejerine-Sottas neuropathy

We report four novel point mutations in the PMP22 gene with two different phenotypes: mutation p.Ser79Thr arose de novo in a patient with the Dejerine-Sottas neuropathy (DSN) phenotype; and mutations c.78+5 G>A, c.320-1 G>C, and p.Trp140Stop segregated with HNPP in 5 families.Our findings show that point mutations in PMP22 may be more likely in HNPP patients than in CMT1 patients after exclusion of CMT1A/HNPP.     

Diagnostic nerve ultrasound in Charcot–Marie–Tooth disease type 1B

Ultrasound is emerging as a useful tool for evaluation of neuromuscular conditions, because it can provide high‐resolution anatomic information to complement electrodiagnostic data. There have been few studies in which ultrasound was used to assess the peripheral nerves of individuals with Charcot–Marie–Tooth (CMT) disease and none involving CMT type 1B. In this study we compared nerve cross‐sectional area in individuals from a single large family with CMT 1B with normal, healthy controls. We also assessed for cranial nerve enlargement in those with CMT 1B with cranial neuropathies compared to those with CMT 1B without cranial neuropathies. Individuals with CMT 1B have significantly larger median and vagus nerves than healthy controls, but no difference was seen in cranial nerve size between those with versus those without cranial neuropathies. This is the first study to characterize the ultrasonographic findings in the peripheral nerves of individuals with CMT 1B. Muscle Nerve 40: 98–102, 2009     

Electromyographic tendon reflex recording: An accurate and comfortable method for diagnosis of charcot‐marie‐tooth disease type 1a

Introduction: We analyzed the utility of tendon reflex (T‐reflex) testing in Charcot‐Marie‐Tooth disease type 1A (CMT1A). Methods: A total of 82 subjects from 27 unrelated CMT1A pedigrees were evaluated prospectively. The series also comprised 28 adult healthy controls. Electrophysiology included evaluation of biceps T‐reflex and soleus T‐reflex. Results: Seventy‐one individuals (62 adults and 9 children) had clinical and electrophysiological features of CMT1A. The remaining 11 (8 adults and 3 children) were unaffected. On electrophysiological testing, the biceps T‐reflex was elicited in 58 of 62 (93%) adult CMT1A patients and in all 9 affected children. Latencies of the biceps T‐reflex were always markedly prolonged, and a cut‐off limit of 16.25 ms clearly separated adult patients and controls or unaffected kin adult individuals. In affected children, the soleus T‐reflex latency was also prolonged when compared with age and height normative data. Conclusion: T‐reflex testing is an accurate diagnostic technique for CMT1A patients. Muscle Nerve 52 : 39–44, 2015     

A Patient with neurofibromatosis type 1 and Charcot–Marie–Tooth disease type 1B

We describe a patient with both neurofibromatosis type 1 and Charcot–Marie–Tooth disease type 1B. Although one might expect an overwhelming tumor burden due to the combination of these two disorders, the two mutations did not appear to interact. Muscle Nerve 41: 555–558, 2010     

Evolution of foot and ankle manifestations in children with CMT1A

We studied the timing and progression of foot and ankle changes in 81 children with genetically confirmed Charcot–Marie–Tooth disease type 1A (CMT1A) and determined their impact on motor function and walking ability. Foot deformity, weakness, pain, cramps, and instability were a common feature of CMT1A. Foot structure evolved toward pes cavus from early childhood to adolescence, although a subgroup with normal and planus feet remained. Foot strength increased with age, although compared to age‐equivalent norms it declined from 4 years. Factors associated with evolving foot deformity included muscle weakness/imbalance, restricted ankle flexibility, and joint hypermobility. Regression modeling identified dorsiflexion weakness, global foot weakness, and difficulty toe‐walking as independent predictors of motor dysfunction, while pes cavus and difficulty heel‐walking were predictors of poor walking ability. Foot problems are present from the earliest stages of the disease and can have a negative impact on function. Early foot and ankle intervention may prevent long‐term disability and morbidity in CMT1A. Muscle Nerve 39: 158–166, 2009     

高通量测序技术与多重连接探针依赖扩增技术在PMP22全基因分析中的应用比较

目的探讨高通量测序技术与多重连接探针依赖扩增(MLPA)技术检测周围神经髓鞘蛋白22基因(PMP22)全基因突变中的应用比较。方法收集5例拟诊为腓骨肌萎缩症1型(CMT1)/遗传性压迫易感性神经病(HNPP)患者的外周血标本,采用高通量测序技术进行PMP22基因检测。结果高通量测序技术检测的基因全长捕获测序分析发现PMP22基因缺失突变1例,重复突变3例,所得结果与MLPA检测结果一致;点突变1例与一代测序(Sanger测序)结果一致。结论应用高通量测序技术不仅能准确检测出PMP22基因点突变,还能检出外显子缺失和重复突变,为CMT1和HNPP患者的早期诊断、鉴别诊断、预后判断及产前诊断提供遗传学帮助,成为一站式PMP22基因检测平台。     

经基因确诊的遗传性压力易感性周围神经病的临床与神经电生理分析

目的:探讨遗传性压力易感性周围神经病(HNPP)的临床、神经电生理及基因特点,为该病的诊断提供依据.方法:对3例患者进行临床特点总结、行电生理检查和基因检测.结果:3例患者均表现为无痛性下肢远端无力.电生理检查示四肢广泛神经传导速度减慢.基因检测示3例患者均存在周围髓鞘蛋白22(PMP22)基因缺失突变.结论:HNPP多以神经易卡压部位发病,表现为受累神经支配区的运动感觉异常,神经电生理表现为广泛神经脱髓鞘损伤,基因检测能确诊.     

Rigid spine syndrome associated with sensory‐motor axonal neuropathy resembling Charcot–Marie‐Tooth disease is characteristic of Bcl‐2‐associated athanogene‐3 gene mutations even without cardiac involvement

Introduction: Bcl‐2‐associated athanogene‐3 (BAG3) mutations have been described in rare cases of rapidly progressive myofibrillar myopathies. Symptoms begin in the first decade with axial involvement and contractures and are associated with cardiac and respiratory impairment in the second decade. Axonal neuropathy has been documented but usually not as a key clinical feature. Methods: We report a 24‐year‐old woman with severe rigid spine syndrome and sensory‐motor neuropathy resembling Charcot–Marie–Tooth disease (CMT). Results: Muscle MRI showed severe fat infiltration without any specific pattern. Deltoid muscle biopsy showed neurogenic changes and discrete myofibrillar abnormalities. Electrocardiogram and transthoracic echocardiography results were normal. Genetic analysis of a panel of 45 CMT genes showed no mutation. BAG3 gene screening identified the previously reported c.626C>T, pPro209Leu, mutation. Discussion: This case indicates that rigid spine syndrome and sensory‐motor axonal neuropathy are key clinical features of BAG3 mutations that should be considered even without cardiac involvement. Muscle Nerve, 57 : 330–334, 2018     

X‐linked Charcot–Marie–Tooth disease predominates in a cohort of multiethnic Malaysian patients

Introduction: Data regarding Charcot–Marie–Tooth disease is lacking in Southeast Asian populations. We investigated the frequency of the common genetic mutations in a multiethnic Malaysian cohort. Methods: Patients with features of Charcot–Marie–Tooth disease or hereditary liability to pressure palsies were investigated for PMP22 duplication, deletion, and point mutations and GJB1, MPZ, and MFN2 point mutations. Results: Over a period of 3 years, we identified 25 index patients. A genetic diagnosis was reached in 60%. The most common were point mutations in GJB1, accounting for X‐linked Charcot–Marie–Tooth disease (24% of the total patient population), followed by PMP22 duplication causing Charcot–Marie–Tooth disease type 1A (20%). We also discovered 2 novel GJB1 mutations, c.521C>T (Proline174Leucine) and c.220G>A (Valine74Methionine). Conclusions: X‐linked Charcot–Marie–Tooth disease was found to predominate in our patient cohort. We also found a better phenotype/genotype correlation when applying a more recently recommended genetic approach to Charcot–Marie–Tooth disease. Muscle Nerve 49 : 198–201, 2014     

Age‐related changes in motor unit number estimates in adult patients with Charcot–Marie–Tooth type 1A

Background: Charcot–Marie–Tooth disease type 1A (CMT1A) is known as a demyelinating hereditary neuropathy. Secondary axonal dysfunction is the most important determinant of disease severity. In adult patients, clinical progression may be because of further axonal deterioration as was shown with compound muscle action potential (CMAP) amplitude reductions over time. The motor unit number estimation (MUNE) technique may be more accurate to determine the number of axons as it is not disturbed by the effect of reinnervation. The purpose of this study was to investigate the number and size of motor units in relation to age in patients and controls. Methods: In a cross‐sectional design, we assessed arm and hand strength and performed electrophysiological examinations, including CMAP amplitudes and MUNE of the thenar muscles using high‐density surface EMG in 69 adult patients with CMT1A and 55 age‐matched healthy controls. Results: In patients, lower CMAP amplitudes and MUNE values were related to hand weakness. The CMAP amplitude and MUNE value of the thenar muscles were significantly lower in patients than in controls. CMAP amplitudes declined with age in controls, but not in patients. MUNE values declined with age in both patients and controls. Conclusions: The age‐dependent decrease in the number of motor units was not significantly different between patients with CMT1A and controls, indicating that loss of motor units in adult patients is limited.     

Molecular diagnosis of PMP22-associated neuropathies using fluorescence in situ hybridization (FISH) on archival peripheral nerve tissue preparations

Charcot-Marie-Tooth (CMT) syndrome type 1 and tomaculous neuropathy, also called hereditary neuropathy with liability to pressure palsies (HNPP), represent two groups of neurological disorders with different subtypes, which can be distinguished at the molecular level. It is known that a 1.5-mb region on chromosome 17p11.2– 12, which includes the gene for the peripheral myelin protein 22 kDa (PMP22), is duplicated in more than 95% of patients with CMT type 1A (CMT1A; gene dosage 3) and is deleted in about 90% of subjects suffering from HNPP (gene dosage 1). This duplication/deletion can be detected reliably by interphase-two-color fluorescence in situ hybridization (FISH). We report here a technique for extraction of nuclei from paraffin-embedded and cryofixed sural nerve biopsies for precise molecular diagnosis, employing interphase-two-color FISH in clinically diagnosed CMT1 or HNPP patients. Following this technique we were able to identify six CMT1A duplications in 13 clinically diagnosed CMT1 cases and five HNPP deletions in 6 clinically diagnosed HNPP cases; 8 control persons were included in this study. This is the first report on the use of FISH in the detection of 17p11.2–12 duplication and deletion in archival biopsy material. Received: 10 January 1997 / Revised, accepted: 3 March 1997