Inherited Myokymia: A Clinical and Genetic Study of a Family

China Medical University

Status: Unknown

Conditions: A Study of Clinical and Genetic Mutations in a Family of Neuromyotonia, so Called Isaac's Syndrome

Study type: Observational

Funder types: Other

Identifiers

NCT01250704

DMR99-IRB-190

Details and patient eligibility

About

Neuromyotonia (NMT), so called Isaac's syndrome, is a rare disorder in which hyperexcitability of peripheral motor nerves leads to intermittent muscle contractions. It is characterized by muscle twitching at rest (visible myokymia), cramps, hyperhidrosis, paraesthesiae, mild muscle weakness. and impaired muscle relaxation, or pseudomyotonia. Electromyographic recording is a key diagnostic tool in detecting myokymia and neuromyotonia. Pathophysiology of neuromyotonia is claimed to be related immune disorder, autoimmune anti-voltage-gated potassium-channel antibodies and genetic mutation in potassium channel. KCNA1 (Kv1.1) mutation was mostly reported in a autosomal dominant trait. In the present study, we report a family affected with myokymia，worsening with elevated body temperature, febrile illness or spicy food. How the change in temperature influence clinical features of channelopathies is an interesting topic. Variant clinical severity of family members are recorded. The index patient has possible autoimmune mechanism involvement because of his clinical feature of myasthenia gravis with thymoma and hyperthyroidism. Further analyzing the genetic mutation in potassium channelopathy may provide researchers some pathophysiological insight into the Isaac's syndrome.

Enrollment: 18 estimated patients

Sex: All

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• The disease was initially diagnosed of Isaacs syndrome by two neurologist(Dr Tsai and Dr Yang). We will recruit family members of diseased patient and normal subjects for clinical, electromyographic and genetic studies.

Exclusion criteria

• none