characterized by muscle stiffness and an inability of the muscle to quickly relax after voluntary contraction. although myotonia can affect any skeletal muscles, including muscles of the face and tongue, it occurs most often in the legs. myotonia causes muscle stiffness (a myotonic disorder should be considered in the differential diagnosis of a patient complaining of muscle stiffness) that can...

The two most common forms of non-dystrophic myotonia (NDM) are congenita (Thomsen disease or Becker-type) and paramyotonia congenita. Symptoms, including muscle stiffness, cramps, transient weakness, can affect a person’s quality life. An unmet need for validated tool to assess symptom severity frequency, as well disability caused by myotonia, led the development Clinical Myotonia Rating Scale ...

We describe the case of a girl with a probable autosomal recessive form of nondystrophic hereditary myotonia whose clinical findings are more compatible with the dominant ones mainly myotonia congenita of Thomsen or myotonia fluctuans. Besides the clinical aspects of the atypical form presented by our patient, the efficacy of the more available drugs employed for the treatment of myotonia conge...

We investigated electrophysiologically the unaffected parents of patients with recessive myotonia congenita. We studied 18 families, in nine of which the diagnosis was confirmed by molecular genetics. Brief myotonic discharges were present in at least one parent in 67% of the families. Fathers were more likely than mothers to show these discharges. The difficulty in distinguishing very mildly a...

congenital recessive myotonia is a rare genetic disorder caused by mutations in clcn1, which codes for the main skeletal muscle chloride channel clc-1. more than 120 mutations have been found in this gene. the main feature of this disorder is muscle membrane hyperexcitability. here, we report a 59-year male patient suffering from congenital myotonia. he had transient generalized myotonia, which...

In isolated fiber bundles of external intercostal muscle from each of 13 normal volunteers and each of 6 patients with myotonia congenita, some or all of the following were measured: concentrations of Na(+), K(+), and Cl(-), extracellular volume, water content, K(+) efflux, fiber size, fiber cable parameters, and fiber resting potentials. Muscle from patients with myotonia congenita differed si...

INTRODUCTION Myotonia Congenita is an inherited myotonia that is due to a mutation in the skeletal muscle chloride channel CLCN1. These mutations lead to reduced sarcolemmal chloride conductance, causing delayed muscle relaxation that is evident as clinical and electrical myotonia. METHODS We report the clinical presentations of two individuals with Myotonia Congenita (MC). RESULTS Patient ...

We describe the case of a six year old boy with findings consistent with myotonia congenita: muscular hypertrophy, stiffness when commencing movements and typical warm-up signs. The most prominent symptom was myotonia of the eyelid muscles with apparent swelling around the eyes. Even though the pronounced warm-up phenomena in our patient suggested a chloride channel-associated myotonia congenit...

Myotonia congenita (MC) is a genetic disease that displays impaired relaxation of skeletal muscle and muscle hypertrophy. This disease is mainly caused by mutations of CLCN1 that encodes human skeletal muscle chloride channel (CLC-1). CLC-1 is a voltage gated chloride channel that activates upon depolarizing potentials and play a major role in stabilization of resting membrane potentials in ske...