Nondystrophic Myotonias

NMD are rare ion channel disorders. The optimal management and treatment of these disorders are not known. This multi-center proposal will allow the prospective collection of standardized data from a critical number of patients to help better define the clinical features of NDM. The data will also be used to establish clinically relevant endpoints for use in therapeutic trials. The identification and genetic characterization of patients will facilitate recruitment of participants for future therapeutic trials. Ultimately, the information gained will lead to the improvements in the treatment and management of NMD with an associated reduction in morbidity and improvement in patient quality of life.]]>
CINCH 5303 ProtocolDrop Down Mutation ChangeNDM Baseline/Screening Information FormNDM Contact and Demographics FormNDM Eligibility Criteria FormNDM Family History Interview FormNDM Local Checklist Form 2007NDM Investigators Clinical Diagnosis FormNDM Local Checklist Form 2006NDM Prolonged Exercise Test Form 2007NDM Prolonged Exercise Test Form 2009NDM Investigators Clinical Diagnosis FormNDM Nerve Conduction/EMG FormNDM Physical Exam/Laboratory FormNDM Quantitative Testing FormNDM Results for Laboratory Testing FormNDM Short Exercise Electro Physiologic Testing FormNDM Symptoms FormInclusion Criteria (Participants must meet 1,2,3,4,5;or1,2,3,4,6): At least 6 years of age. Clinical symptoms or signs suggestive of myotonic disorders. Presence of myotonic potentials on electromyography (EMG). Persistence of symptoms and signs after discontinuation of medications that produce myotonia: a. Fibrate acid derivatives b. Hydroxymethylglutaryl CoA reductase inhibitors c. Chloroquine d. Colchicine Absence of features suggestive of myotonic dystrophy 1 a. Ptosis b. Temporal wasting c. Mandibular weakness d. Cataracts occurring before age 50 e. Evidence of multisystem defects (cardiac conduction defects, hypogonadism) Or negative genetic test for DM1 (CTG repeat < 100) if patient has clinical feature/s as in criteria 5. Exclusion Criteria Inability or unwillingness to provide informed consent. Other neurologic conditions that might affect the assessment of the study measurements. Genetically confirmed DM1 (CTG repeat >100). ]]>
The myotonic muscle disorders represent a heterogeneous group of clinically similar diseases sharing the feature of myotonia: delayed relaxation of muscle after voluntary contraction (action myotonia) or mechanical stimulation (percussion myotonia). In classic myotonia, the myotonia improves as muscles warm up, whereas in paradoxical myotonia (paramyotonia) it worsens with repeated muscle contractions. Electrophysiologically, myotonia is characterized by the repetitive electrical activity of muscle fibers. Nondystrophic types of myotonia can be identified by their clinical features and molecular defect. The nondystrophic myotonias are clinically heterogeneous and have been traditionally divided into three categories: hyperkalemic periodic paralysis, paramyotonia congenita, and myotonia congenita.]]>