Coexistence of Charcot-Marie-Tooth 1A and nondystrophic myotonia due to PMP22 duplication and SCN4A pathogenic variants: a case report.

BACKGROUND: Charcot-Marie-Tooth disease (CMT) is a genetically heterogeneous hereditary neuropathy, and CMT1A is the most common form; it is caused by a duplication of the peripheral myelin protein 22 (PMP22) gene. Mutations in the transient sodium channel Nav1.4 alpha subunit (SCN4A) gene underlie a diverse group of dominantly inherited nondystrophic myotonias that run the spectrum from subclinical myopathy to severe muscle stiffness, disabling weakness, or frank episodes of paralysis. CASE PRESENTATION: We describe a Chinese family affected by both CMT1A and myotonia with concomitant alterations in both the PMP22 and SCN4A genes. In this family, the affected proband inherited the disease from his father in an autosomal dominant manner. Genetic analysis confirmed duplication of the PMP22 gene and a missense c.3917G > C (p. Gly1306Ala) mutation in SCN4A in both the proband and his father. The clinical phenotype in the proband showed the combined involvement of skeletal muscle and peripheral nerves. Electromyography showed myopathic changes, including myotonic discharges. MRI revealed the concurrence of neurogenic and myogenic changes in the lower leg muscles. Sural nerve biopsies revealed a chronic demyelinating and remyelinating process with onion bulb formations in the proband. The proband's father presented with confirmed subclinical myopathy, very mild distal atrophy and proximal hypertrophy of the lower leg muscles, pes cavus, and areflexia. CONCLUSION: This study reports the coexistence of PMP22 duplication and SCN4A mutation. The presenting features in this family suggested that both neuropathy and myopathy were inherited in an autosomal dominant manner. The proband had a typical phenotype of sodium channel myotonia (SCM) and CMT1A. However, his father with the same mutations presented a much milder clinical phenotype. Our study might expand the genetic and phenotypic spectra of neuromuscular disorders with concomitant mutations.

Sympathetic outflow to skin predicts central autonomic dysfunction in multiple system atrophy.

BACKGROUND: To find out the physiological method for evaluating the severity of central autonomic dysfunction, we performed detailed evaluation of cutaneous vasomotor neural function in a comparatively large sample of multiple system atrophy (MSA). METHODS: We evaluated cutaneous vasomotor neural function in 24 MSA patients. Skin sympathetic nerve activity (SSNA) and sympathetic skin response (SSR) and skin blood flow (skin vasomotor reflex [SVR]) were recorded at rest, as well as reflex changes after electrical stimulation. The parameters investigated were SSNA frequency at rest, reflex latency and amplitude of SSNA reflex bursts, absolute decrease and percent reduction of SVR, recovery time, and spontaneous SVR and SSR frequency. RESULTS: There were negative correlations between resting SSNA and disease duration or the SCOPA-AUT score, but these were not significant. SSNA reflex latency displayed significant positive correlations with disease duration and SCOPA-AUT score (p < 0.001 and p < 0.01, respectively). In all five patients who underwent the same examination twice, SSNA reflex latency was significantly longer at the second examination than at the first examination (p < 0.005). A significant positive correlation was identified between recovery time of skin blood flow and SCOPA-AUT score or reflex latency (p < 0.05). Significant correlations were not observed between SCOPA-AUT score or disease duration and other parameters. CONCLUSIONS: These results suggest that some MSA patients with a comparatively short duration of disease potentially have impaired thermoregulatory function. Measurement of sympathetic outflow to the skin is potentially a useful tool for predicting the severity of central autonomic dysfunction in MSA.

Pathological findings in a patient with non-dystrophic myotonia with a mutation of the SCN4A gene; a case report.

BACKGROUND: Non-dystrophic myotonias (NDMs) are skeletal muscle disorders involving myotonia distinct from myotonic dystrophy. It has been reported that the muscle pathology is usually normal or comprises mild myopathic changes in NDMs. We describe various pathological findings mimicking those of myotonic dystrophy (DM) in biopsied muscle specimens from a patient with NDMs with a long disease duration. CASE PRESENTATION: A 66-year-old Japanease man presented eye closure myotonia, percussion myotonia and grip myotonia together with the warm-up phenomenon and cold aggravation from early childhood. On genetic analysis, a heterozygous mutation of the SCN4A gene (c.2065 C > T, p.L689F), with no mutation of the CLCN1, DMPK, or ZNF9/CNBP gene, was detected. He was diagnosed as having NDMs. A biopsy of the biceps brachii muscle showed increasing fiber size variation, internal nuclei, chained nuclei, necrotic fibers, fiber splitting, endomysial fibrosis, pyknotic nuclear clumps and disorganized intermyofibrillar networks. Sarcoplasmic masses, tubular aggregates and ragged-red fibers were absent. CONCLUSION: It is noteworthy that the present study revealed various pathological findings resembling those seen in DM, although the pathology is usually normal or mild in NDMs. The pathological similarities may be due to muscular modification with long-standing myotonia or excessive muscle contraction based on abnormal channel activity.

Vasomotor regulation in patients with multiple system atrophy.

To investigate the vasomotor regulation in multiple system atrophy (MSA), we simultaneously recorded muscle sympathetic nerve activity (MSNA), heart rate, and blood pressure in 14 MSA patients without syncope and 18 healthy subjects. Resting MSNA bursts were significantly less frequent in MSA patients than healthy subjects (p < 0.001), while the increase of MSNA bursts with head-up tilt was significantly greater in MSA patients (p < 0.01). In patients with MSA, orthostatic hypotension may be prevented by an augmented MSNA response.

Muscle sympathetic nerve activity in frontotemporal lobar degeneration is similar to amyotrophic lateral sclerosis.

PURPOSE: To determine whether frontotemporal lobar degeneration (FTLD) is associated with similar cardiovascular autonomic dysfunction to that seen in amyotrophic lateral sclerosis (ALS), we compared cardiovascular parameters between ALS patients and patients with FTLD. METHODS: In ten patients with FTLD (mean age ± SD: 71.6 ± 4.6 years) and 12 patients with ALS (mean age ± SD: 71.4 ± 4.6 years), MSNA (using microneurography), heart rate (HR), and blood pressure (BP) were recorded simultaneously. RESULTS: MSNA was significantly higher in both groups of patients compared with the controls (p < 0.01), while there were no significant differences in MSNA between the patients with FTLD and those with ALS. During head-up tilt, changes in HR, BP, and the frequency of MSNA bursts were smaller in the patients than in controls (p < 0.05 or p < 0.01). CONCLUSIONS: Patients with FTLD and ALS showed similar dysfunction of HR, BP, and sympathetic outflow to muscles.

Changes in sympathetic thermoregulatory function with aging.

We recorded skin sympathetic nerve activity (SSNA), SSR, and SVR in 30 subjects. SSNA and SVR showed a slight decrease and spontaneous changes in resting SSR were significantly less frequent in older subjects compared with younger subjects (p < 0.05). There was no significant relationship between age and the reflex latency or amplitude of SSNA, SSR, and SVR in response to electrical stimulation.

Temporal prolongation of decreased skin blood flow causes cold limbs in Parkinson's disease.

To unravel the pathogenesis of cold limbs in Parkinson's disease, we evaluated cutaneous vasomotor neural function in 25 Parkinson's disease patients with or without cold limbs and 20 healthy controls. We measured resting skin sympathetic nerve activity, as well as reflex changes of skin blood flow and skin sympathetic nerve activity after electrical stimulation, with the parameters including skin sympathetic nerve activity frequency at rest, the amplitude of reflex bursts, the absolute decrease and percent reduction of blood flow, and the recovery time which was calculated as the interval from the start of blood flow reduction until the return to baseline cutaneous blood flow. The resting frequency of skin sympathetic nerve activity was significantly lower in patients with Parkinson's disease than in controls (p < 0.01). There were no significant differences between the patients and controls with respect to the amplitude of skin sympathetic nerve activity and the absolute decrease or percent reduction of blood flow volume. In the controls, the recovery time (9.4 ± 1.2), which was similar to Parkinson's disease patients without cold limbs (9.0 ± 0.7), while the recovery time ranged (15.7 ± 3.2) in Parkinson's disease patients with cold limbs. Recovery was significantly slower in these patients compared with the other groups (p < 0.05). It is possible that cold limbs might arise due to impaired circulation based on prolonged vasoconstriction by peripheral autonomic impairments, in addition to central autonomic dysfunction in Parkinson's disease.

Familial amyloidotic polyneuropathy and transthyretin.

There has been much progress in our understanding of transthyretin (TTR)-related amyloidosis including familial amyloidotic polyneuropathy (FAP), senile systemic amyloidosis and its related disorders from many clinical and experimental aspects. FAP is an inherited severe systemic amyloidosis caused by mutated TTR, and characterized by amyloid deposition mainly in the peripheral nervous system and the heart. Liver transplantation is the only available treatment for the disease. FAP is now recognized not to be a rare disease, and to have many variations based on genetical and biochemical variations of TTR. This chapter covers the recent advances in the clinical and pathological aspects of, and therapeutic approaches to FAP, and the trend as to the molecular pathogenesis of TTR.

Thymoma-associated anti-LGI1 encephalitis and myasthenia gravis: A unique combination with autoantibodies.

We report a 77-year-old woman with a thymoma, anti-LGI1antibody associated encephalitis (LGI1 encephalitis), and MG accompanied by positive anti-acetylcholine receptor antibodies (AchR Ab) and anti-titin antibodies (titin Ab). She was treated with thymomectomy followed by immunosuppressive therapy, which resulted in immediate amelioration of motor weakness and gradual improvement of cognitive impairment over the next two years. LGI1 Ab were positive at two months after thymomectomy, followed by negative conversion demonstrated on 1 year examination. The AchR Ab level had gradually decreased but titin Ab was positive on re-examination after two years, although the cognition and motor impairment symptoms had been alleviated. In patients with suspected autoimmune encephalitis, the detection of several autoantibodies including LGI1 and thymomas provides useful information for making an accurate diagnosis.

Sympathetic sudomotor neural function in amyotrophic lateral sclerosis.

In patients with amyotrophic lateral sclerosis (ALS), sudomotor and vasomotor function have been considered to be impaired based on sympathetic skin response (SSR) or cutaneous blood flow measurements. We evaluated sympathetic sudomotor and vasoconstrictive neural function in ALS. We simultaneously recorded SSR, skin blood flow, and skin sympathetic nerve activity (SSNA) by microneurography in 20 patients with sporadic ALS and 20 healthy controls. Resting frequency of SSNA was significantly higher in ALS patients than in controls (p <0.05), but the increase of SSNA associated with mental arithmetic was smaller in ALS patients than controls (p <0.05). ALS patients also exhibited slight prolongation of SSNA reflex latencies compared with controls (p <0.05). In conclusion, sympathetic hyperactivity was observed in relation to sudomotor and vasoconstrictive skin responses. Since SSNA reflex latencies reflect central sympathetic function, the central autonomic pathways may be slightly impaired in patients with ALS.

[A Case of Parkinson's Disease Associated with Repeated Deterioration of Akinesia/Bradykinesia Due to Hypothermia].

In 2012, a 69-year-old man noticed slowness in his movements and was diagnosed with Parkinson's disease (PD). In December 2017, he was admitted to a hospital with a diagnosis of hypothermia. One month later, in January 2018, he had difficulty moving around at home and was admitted to our hospital because of impaired consciousness. On admission, his consciousness was rated as level II-10, his body temperature was 32.8℃, and he was pale and had extrapyramidal symptoms. Electrocardiogram showed T-wave flattening and the first degree of atrioventricular block. Warming was started with improvement of the level of consciousness on the sixth hospital day. His cognitive function was normal (HDS-R 27/30), but the Schellong test (an orthostatic blood pressure test) showed a marked decrease in systolic blood pressure upon standing. Although sympathetic skin and flow responses were almost normal, except for low levels of basal skin blood flow, we speculated that the patient had impaired thermoregulation due to central autonomic dysfunction. In the literature, such impaired thermoregulation was suggested as the cause of hypothermia in seven patients with PD. Therefore, we recommend that patients with PD and repeated hypothermia should be instructed to maintain a suitable room temperature and to dress warmly. (Received 25 June, 2021; Accepted 31 August, 2021; Published 1 December, 2021).

Sympathetic nerve outflow to skin in a case with dentatorubral-pallidoluysian atrophy.

Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder characterized by slowly progressive cerebellar ataxia. Previously, autonomic symptoms or dysfunction have not been reported. To evaluate subclinical autonomic dysfunction regarding thermoregulatory function in SCA, we recorded sympathetic outflow to skin in a DRPLA patient confirmed by genetic analysis. We recorded skin sympathetic nerve activity (SSNA), which was elicited and recorded by using the microneurographical technique. In results, the resting frequency of SSNA bursts was very low (8.2 ± 0.4 bursts/min [institutional normal range: 20.8 ± 2.4 bursts/min]). However, acceleration of SSNA bursts induced by mental arithmetic stress was confirmed. The amplitude of reflex bursts induced by electrical stimuli was slightly low (9.6 ± 1.6 µV [institutional normal range: 10.9 ± 2.2 µV]), and the reflex latency was mildly prolonged (872 ± 23.7 msec [institutional normal range: 761.9 ± 51.7 msec]). These results suggest potentially central autonomic dysfunction in this patient with DRPLA. To our knowledge, this is the first report to record SSNA and confirm subclinical autonomic dysfunction in a case with DRPLA.

Age-related changes in blood pressure and heart rates of patients with Parkinson's disease.

This study evaluated yearly changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rates (HR) for patients with Parkinson's disease (PD). Data were collected for the last 10 years from medical records of 28 PD patients and 30 non-PD patients with other neurological disorders. Age-related changes in each group were analyzed by year using mean values of SBP, DBP, and HR obtained at their bi-monthly visits. In results, PD patients had a gradual decrease in SBP with longer disease duration, and mean SBP significantly decreased from Year 7-11 compared to the mean values for Year 1 (p < .001 or p < .01). In non-PD patients, mean SBP significantly increased from Year 4-11 compared to the mean values for Year 1 (p < .001 or p < .01). This is the first study to report age-related changes of BP in individual patients with PD over 10 years.

Rhythmic pupillary oscillation in Creutzfeldt-Jakob disease associated with the Glu/Lys mutation of prion protein codon 200.

We report two Creutzfeldt-Jakob disease (CJD) patients with rhythmic pupillary and palpebral oscillation who had a mutation of prion protein codon 200 that resulted in the substitution of lysine for glutamate (Glu/Lys). Alternating dilation and constriction of the pupils combined with elevation and descent of the eyelids occurred in correspondence with periodic sharp wave complexes (PSWCs) on the electroencephalogram and with myoclonus of the head, face, and extremities. The onset of pupillary dilation and palpebral elevation coincided with the PSWCs. Initiation of these rhythmic pupillary and palpebral movements may depend on sympathetic activity, but the site of the generator is unclear. Such rhythmic pupillary and palpebral oscillation may be a feature of rapidly progressive CJD with predominant right hemispheric involvement.

A case of recurrent polymyalgia rheumatica-like complications with pregnancy.

We encountered a 26-year-old Japanese woman with recurrent episodes of polymyalgia rheumatica-like symptoms associated with pregnancy. At a 13-week pregnancy, she was admitted to our outpatient clinic, complaining of myalgia on both thighs, shoulders and upper limbs. Laboratory examinations of blood yielded normal creatine kinase and mild elevation of erythrocyte sedimentation rate. After administration of oral prednisolone (10 mg/day) was begun, her symptoms were gradually resolved by 1 week. Further epidemiologic studies should be needed.

Morphological Alterations of the Sarcotubular System in Permanent Myopathy of Hereditary Hypokalemic Periodic Paralysis with a Mutation in the CACNA1S Gene.

We investigated the immunohistochemical localization of several proteins related to excitation-contraction coupling and ultrastructural alterations of the sarcotubular system in biopsied muscles from a father and a daughter in a family with permanent myopathy with hypokalemic periodic paralysis (PMPP) due to a mutation in calcium channel CACNA1S; p. R1239H hetero. Immunostaining for L-type calcium channels (LCaC) showed linear hyper-stained regions indicating proliferation of longitudinal t-tubules. The margin of vacuoles was positive for ryanodine receptor, LCaC, calsequestrin (CASQ) 1, CASQ 2, SR/ER Ca2+-ATPase (SERCA) 1, SERCA2, dysferlin, dystrophin, α-actinin, LC3, and LAMP 1. Electron microscopy indicated that the vacuoles mainly originated from the sarcoplasmic reticulum (SR). These findings indicate impairment of the muscle contraction system related to Ca2+ dynamics, remodeling of t-tubules and muscle fiber repair. We speculate that PMPP in patients with a CACNA1S mutation might start with abnormal SR function due to impaired LCaC. Subsequent induction of muscular contractile abnormalities and the vacuoles formed by fused SR in the repair process including autophagy might result in permanent myopathy. Our findings may facilitate prediction of the pathomechanisms of PMPP seen on morphological observation.