The clinical presentation of patients varies depending on which nucleotide, codon, or amino acid changes, and the number of mutant exons. [annchildneurol.org]

This presentation is about different diseases which presents or are associated with myotonia. Referrences were taken from Bashir Katirji Neuromuscular textbook, continuum, and seminar of neurology journal. [slideshare.net]

[…] symptoms in 80-99% of the cases: Hypertonia Myotonia Frequently present symptoms in 30-79% of the cases: Elevated serum creatine phosphokinase EMG abnormality Feeding difficulties in infancy Flexion contracture Gait disturbance Myalgia Occasionally present [dovemed.com]

Patients with myotonic dystrophy, in particular myotonic dystrophy type 2, may present with features of myotonia lacking overt weakness, mimicking the presentation of a non-dystrophic myotonic disorder. [now.aapmr.org]

Patients that present with permanent weakness are normally not characterized as having PC. [wikidoc.org]

• Chest Pain

  pain EMG abnormality Myotonia And another 2 symptoms. [mendelian.co]

  Myotonia Frequently present symptoms in 30-79% of the cases: Elevated serum creatine phosphokinase EMG abnormality Feeding difficulties in infancy Flexion contracture Gait disturbance Myalgia Occasionally present symptoms in 5-29% of the cases: Asthma Chest [dovemed.com]

• Irregular Heart Rhythm

  In addition ATS patients experience irregular heart rhythms including a prolonged QT interval. [hkpp.org]

• Joint Stiffness

  […] present symptoms in 30-79% of the cases: Elevated serum creatine phosphokinase EMG abnormality Feeding difficulties in infancy Flexion contracture Gait disturbance Myalgia Occasionally present symptoms in 5-29% of the cases: Asthma Chest pain Hyperkalemia Joint [dovemed.com]

• Flexion Contracture

  […] following information may be noted: Very frequently present symptoms in 80-99% of the cases: Hypertonia Myotonia Frequently present symptoms in 30-79% of the cases: Elevated serum creatine phosphokinase EMG abnormality Feeding difficulties in infancy Flexion [dovemed.com]

• Myelopathy

  […] wasting & weakness Autonomic Hyperhidrosis: Associated with spasms Hyperthermia Failure may occur Cranial nerves EOM: Nystagmus & Ophthalmoplegia Blindness Deafness Dysarthria Other CNS Encephalopathy Long tract signs Vertigo Intellect preserved in some Myelopathy [neuromuscular.wustl.edu]

A complete metabolic workup at 15 months of age was negative. [nature.com]

[…] be used to measure and monitor the effectiveness of drug treatment on symptoms over time. [emjreviews.com]

The treatment is usually given to manage the signs and symptoms and any complication that develops. [dovemed.com]

[…] begins with avoiding foods that contain large amounts of potassium; other treatments may include physical therapy (stretching or massages to help relax muscles) or certain medications (such as mexiletine, carbamazapine, or acetazolamide).[5170] For more [rarediseases.org]

Pharmacologic treatment Pharmocological treatment of myotonia 1. [link.springer.com]

The owner did not report any side effects of long-term acetazolamide treatment. [tandfonline.com]

Early predictions of outcomes A precise phenotypic and genotypic diagnosis is of critcal importance to provide prognosis, determine the most appropriate therapeutic intervention, and for accurate genetic counseling. [now.aapmr.org]

Prognosis is generally excellent. [bioline.org.br]

[…] exercise May be associated with paresthesias Lasts 15 to 60 minutes: Occasionally hours or days Provoked by Exercise Potassium loading Cold environment Pregnancy Glucocorticoids Stress Ethanol Fasting Relieved by: Carbohydrate intake; Mild exercise Prognosis [neuromuscular.wustl.edu]

During the perinatal period, infants with congenital myotonic dystrophy may require continuous ventilator support, and those remaining ventilator-dependent beyond 4 weeks of age have a poor prognosis for survival, although recent advances in neonatal [clinicalgate.com]

(Etiology) Potassium-Aggravated Myotonia is caused by missense mutation(s) in SCN4A gene The SCN4A gene codes for the alpha subunit of the skeletal muscle voltage-gated channel Nav1.4 The proper functioning of this gene is crucial for the proper activation [dovemed.com]

Etiology Autosomal dominant and recessive myotonia congenita (MC) are associated with mutations of the chloride channel gene, CLCN1, in greater than 95% of cases. [now.aapmr.org]

Their etiology is unknown but may relate to the toxic effect of intranuclear accumulations of abnormally expanded RNA. Management of these brain symptoms is similar to that for DM1. [clinicalgate.com]

Etiology ACZ-responsive myotonia is a sodium muscle channelopathy due to missense mutations of the SCN4A gene, encoding the alpha subunit of the skeletal muscle voltage-gated sodium channel Nav1.4. [orpha.net]

PMID: 20298421 Etiology J Mol Neurosci 2017 Mar;61(3):312-314. Epub 2016 Dec 23 doi: 10.1007/s12031-016-0878-5. [ncbi.nlm.nih.gov]

Epidemiological estimates have been provided for the German population. [wikidoc.org]

Other loci; Dominant 9 Epidemiology Most families: CAV3 mutation 1 family: 1q41 linkage CAV3 Genetics Caveolin-3 mutations: Missense R26Q: AD-RMD; HyperCKemia Asp27Glu: Variable phenotype, AD-RMD; Distal weakness; LGMD & Intrafamilial variation A45T: [neuromuscular.wustl.edu]

The Epidemiology of Neuromuscular Disorders: A Comprehensive Overview of the Literature. Journal of neuromuscular diseases 2015;2(1):73-85. Hughes MI, Hicks EM, Nevin NC, Patterson VH. [now.aapmr.org]

For example, DM2 is as prevalent as DM1 in the studied population in Finland and Germany. [11] It is believed that DM mutations are not as prevalent in the Indian subcontinent; however, well-designed genetic epidemiological surveys are needed to better [bioline.org.br]

Pathophysiology The molecular mechanisms leading to the manifestations of DM2 are believed to be similar to that in DM1, and relate to a toxic effect of the abnormally expanded RNA that accumulates in the muscle nuclei (see previous section on Pathophysiology [clinicalgate.com]

This pathophysiological mechanism can lead to an initial burst of myotonia discharges and results in the symptom of stiffness. [annchildneurol.org]

[…] o=5653 Full size table Treatment of myotonia Pathophysiology Physiologically myotonia can be interpreted as an increase in muscle membrane excitability. [link.springer.com]

They are classified based on their clinical symptoms, genetics, pathophysiology and response to treatment. PKD episodes are triggered by sudden movement and are brief (Bhatia 2011). [tandfonline.com]

Pathophysiology Paramyotonia congenita (as well as hyperkalemic periodic paralysis and the potassium-aggravated myotonias) is caused by mutations in a sodium channel, SCN4A. The phenotype of patients with these mutations is indicated in Table 1. [wikidoc.org]

People with this disease will continue to show a continuous burst of muscle tension (muscle stiffness) that prevents the muscles from relaxing normally. [acroscell.creative-bioarray.com]

Currently, Potassium-Aggravated Myotonia may not be preventable, since it is a genetic disorder. [dovemed.com]

Successful treatment of paramyotonia congenita (Eulenburg): muscle stiffness and weakness prevented by tocainide. J Neurol, Neurosurg, & Psychiatry 1980; 43:268–271.CrossRefGoogle Scholar 14.Griggs, RC, Moxley, RT III, Riggs, JE, Engel, WK. [cambridge.org]

Monitoring of electrolytes in particular serum potassium levels to prevent hyperkalaemia may be necessary. [link.springer.com]

Avoidance of myotonia triggering events is also an effective method of mytonia prevention. Epidemiology Paramyotonia congenita is considered an extremely rare disorder, though little epidemiological work has been done. [wikidoc.org]