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Journal of Medical Genetics Jun 1972
Topics: Child, Preschool; Consanguinity; Electromyography; Female; Genes, Recessive; Humans; Male; Myotonia Congenita; Pedigree
PubMed: 5046632
DOI: 10.1136/jmg.9.2.213 -
Journal of the South African Veterinary... Jun 2009A 4-month-old male Jack Russell terrier was evaluated for non-painful muscle spasms and collapse associated with exercise and activity. Clinical examination revealed...
A 4-month-old male Jack Russell terrier was evaluated for non-painful muscle spasms and collapse associated with exercise and activity. Clinical examination revealed well-defined, non-painful hypertrophic muscles of the fore and hind limbs and exercise and excitement induced hindquarter bunny-hopping gait, which improved with activity but worsened with resting and with any sudden changes in direction of movement. Neurological examination and routine laboratory testing showed no abnormalities. DNA analysis for myotonia congenita showed the dog to have a gene mutation in the chloride ion channel, diagnostic for myotonia congenita, which has not been reported in the Jack Russell terrier breed.
Topics: Animals; Chloride Channels; Dog Diseases; Dogs; Genetic Predisposition to Disease; Male; Muscle, Skeletal; Mutation; Myotonia Congenita
PubMed: 19831273
DOI: 10.4102/jsava.v80i2.181 -
Muscle & Nerve Jun 2014Myotonia congenita (MC) is caused by congenital defects in the muscle chloride channel CLC-1. This study used muscle velocity recovery cycles (MVRCs) to investigate how...
INTRODUCTION
Myotonia congenita (MC) is caused by congenital defects in the muscle chloride channel CLC-1. This study used muscle velocity recovery cycles (MVRCs) to investigate how membrane function is affected.
METHODS
MVRCs and responses to repetitive stimulation were compared between 18 patients with genetically confirmed MC (13 recessive, 7 dominant) and 30 age-matched, normal controls.
RESULTS
MC patients exhibited increased early supernormality, but this was prevented by treatment with sodium channel blockers. After multiple conditioning stimuli, late supernormality was enhanced in all MC patients, indicating delayed repolarization. These abnormalities were similar between the MC subtypes, but recessive patients showed a greater drop in amplitude during repetitive stimulation.
CONCLUSIONS
MVRCs indicate that chloride conductance only becomes important when muscle fibers are depolarized. The differential responses to repetitive stimulation suggest that, in dominant MC, the affected chloride channels are activated by strong depolarization, consistent with a positive shift of the CLC-1 activation curve.
Topics: Adult; Aged; Case-Control Studies; Chloride Channels; Electric Stimulation; Female; Humans; Male; Middle Aged; Muscle, Skeletal; Myotonia Congenita; Reaction Time; Recovery of Function; Sodium Channel Blockers; Time Factors
PubMed: 24037712
DOI: 10.1002/mus.24069 -
Neurologia I Neurochirurgia Polska 2022In myotonia congenita (MC), activation with exercise or cooling can induce transient changes in compound motor action potential (CMAP) parameters, thus providing a guide...
INTRODUCTION
In myotonia congenita (MC), activation with exercise or cooling can induce transient changes in compound motor action potential (CMAP) parameters, thus providing a guide to genetic analysis.
MATERIAL AND METHODS
We performed the short exercise test (SET) and the short exercise test with cooling (SETC) in 30 patients with genetically confirmed Becker disease (BMC) to estimate their utility in the diagnosis of BMC.
RESULTS
Although we observed a significant decrease in CMAP amplitude immediately after maximal voluntary effort in both tests in the whole BMC group, in men this decline was significantly smaller than in women, especially in SET. Clinical implications/future directions: In men with a clinical suspicion of BMC, a small decrease in CMAP amplitude in SET together with a typical decline in SETC does not exclude the diagnosis of BMC. Our results show a sex-specific difference in chloride channel function in BMC, which needs further investigation.
Topics: Female; Humans; Male; Myotonia Congenita; Sex Characteristics; Electromyography; Action Potentials; Mutation
PubMed: 35792560
DOI: 10.5603/PJNNS.a2022.0051 -
Muscle & Nerve Feb 2013
Topics: Aged; Blepharoptosis; Diplopia; Female; Humans; Myotonia Congenita
PubMed: 23349086
DOI: 10.1002/mus.23634 -
Molecular Biology Reports Jun 2024Myotonia Congenita (MC) is a rare disease classified into two major forms; Thomsen and Becker disease caused by mutations in the CLCN1 gene, which affects muscle...
BACKGROUND
Myotonia Congenita (MC) is a rare disease classified into two major forms; Thomsen and Becker disease caused by mutations in the CLCN1 gene, which affects muscle excitability and encodes voltage-gated chloride channels (CLC-1). While, there are no data regarding the clinical and molecular characterization of myotonia in Egyptian patients.
METHODS
Herein, we report seven Egyptian MC patients from six unrelated families. Following the clinical diagnosis, whole-exome sequencing (WES) was performed for genetic diagnosis. Various in silico prediction tools were utilized to interpret variant pathogenicity. The candidate variants were then validated using Sanger sequencing technique.
RESULTS
In total, seven cases were recruited. The ages at the examination were ranged from eight months to nineteen years. Clinical manifestations included warm-up phenomenon, hand grip, and percussion myotonia. Electromyography was performed in all patients and revealed myotonic discharges. Molecular genetic analysis revealed five different variants. Of them, we identified two novel variants in the CLCN1 gene ( c.1583G > C; p.Gly528Ala and c.2203_2216del;p.Thr735ValfsTer57) and three known variants in the CLCN1 and SCN4A gene. According to in silico tools, the identified novel variants were predicted to have deleterious effects.
CONCLUSIONS
As the first study to apply WES among Egyptian MC patients, our findings reported two novel heterozygous variants that expand the CLCN1 mutational spectrum for MC diagnosis. These results further confirm that genetic testing is essential for early diagnosis of MC, which affects follow-up treatment and prognostic assessment in clinical practice.
Topics: Humans; Myotonia Congenita; Exome Sequencing; Chloride Channels; Female; Male; Egypt; Child; Adolescent; Mutation; Child, Preschool; Young Adult; Infant; NAV1.4 Voltage-Gated Sodium Channel; Adult; Pedigree; Electromyography
PubMed: 38877370
DOI: 10.1007/s11033-024-09646-8 -
The Journal of Small Animal Practice Oct 1998FELINE infections peritonitis (FIP) is a systemic, fatal, immune‐mediated vasculitis caused by a feline coronavirus (FCoV). Historically, FIP virus (FIPV) and feline...
FELINE infections peritonitis (FIP) is a systemic, fatal, immune‐mediated vasculitis caused by a feline coronavirus (FCoV). Historically, FIP virus (FIPV) and feline enteritis by a feline enteric coronavirus (FECV). Recent studies have shown that there is essentially only one FCoV in the field, although laboratory strains may vary in virulence.
Topics: Animals; Cat Diseases; Cats; Myotonia Congenita
PubMed: 9816575
DOI: 10.1111/j.1748-5827.1998.tb03690.x -
Neurologija 1978
Topics: Adult; Humans; Male; Myotonia Congenita
PubMed: 754020
DOI: No ID Found -
Italian Journal of Neurological Sciences Oct 1982A descriptive epidemiological survey of Myotonia Congenita (MC) and Myotonic Dystrophy (MD) was carried out on the resident population of the City of Turin, Italy. Cases...
A descriptive epidemiological survey of Myotonia Congenita (MC) and Myotonic Dystrophy (MD) was carried out on the resident population of the City of Turin, Italy. Cases were collected from the Archives of the Neurological Clinic, University of Turin, and from other neurological departments in the city's hospitals. Every patient (and the "healthy" relatives of MD subjects) underwent clinical and EMG re-examination, in order to confirm the initial diagnosis and to investigate the familial distribution of the diseases. The point prevalence rate was 0.9 (+/- 0.6) X 10(-5) for MC and 2.1 (+/- 0.8) X 10(-5) for MD. During the period 1955-1979 the mean annual incidence was 0.3 (+/- 0.2) X 10(-6) for MC and 0.7 (+/- 0.3) X 10(-6) for MD. The incidence-at-birth rate was 1.4 (+/- 1.2) X 10(-5) for MC and 2.9 (+/- 1.8) X 10(-5) for MD. The modalities of inheritance and sex distribution of MC and MD were also studied. Knowledge of epidemiological features of these myopathies is of vital importance for genetic counselling.
Topics: Female; Humans; Infant, Newborn; Italy; Male; Myotonia Congenita; Myotonic Dystrophy
PubMed: 7161034
DOI: 10.1007/BF02043311 -
Fortschritte Der Neurologie-Psychiatrie Sep 2022Myotonia congenita was first described as an entity in 1876 by Julius Thomsen. Shortly later in the same year it was criticized by Adolph Seeligmüller who extended the...
Myotonia congenita was first described as an entity in 1876 by Julius Thomsen. Shortly later in the same year it was criticized by Adolph Seeligmüller who extended the clinical findings. Charles Bell, Moritz Benedict and Ernst von Leyden had already partly described the symptoms of the disease before 1876, but did not recognize this as a new entity. A comparison of the publications of Thomsen and Seeligmüller in 1876 and of Seeligmüller's textbook published in 1887, as well as the today's genetically proven disease shows that Seeligmüller correctly criticized two aspects of Thomsen's publication: (i) Thomsen suspected the pathogenesis to be in "one half of the brain's activity, the will" with "seat in the cerebrospinal system" and (ii) he made the assumption of a coordination disorder in the sense of an ataxia [1]. Due to a better understanding of the pathogenesis enabled by Seeligmüller's postulate of a "more difficult mobile muscle substance" [2] without excluding an inborn affection of the lateral cords of the spinal cord, it would have been entirely justified to recognize Seeligmüller's contribution to the conceptual history of Myotonia congenita by including his name in the eponym [3].
Topics: Humans; Male; Muscles; Myotonia Congenita
PubMed: 34448176
DOI: 10.1055/a-1552-3528