Mutations of SCN4A encoding the skeletal muscle sodium channel Nav 1.4 cause several types of disease, including sodium channel myotonias. The latter may be responsible for neonatal symptoms, including severe neonatal episodic laryngospasm (SNEL). Establishing the diagnosis of SCN4A-related SNEL early in the neonatal period is crucial because treatment is available that can reduce laryngospasm ...

Familial hyperkalemic periodic paralysis is an autosomal-dominant channelopathy characterized by reversible paralysis associated with episodic hyperkalemia. Mutations in the skeletal muscle voltage-gated sodium channel gene (SCN4A) have been reported to be responsible for this disorder. Paramyotonia congenita is also caused by mutations in the SCN4A gene. Here, we report the case of a 17-year-o...

OBJECTIVES To characterise the clinical and electrophysiological features and to determine the molecular genetic basis of pure paramyotonia congenita in a previously unreported large Irish kindred. METHODS Clinical and neurophysiological examination was performed on three of the five affected family members. Five unaffected and three affected members of the family were available for genetic t...

Essential tremor (ET) is the most prevalent movement disorder, affecting millions of people in the USA. Although a positive family history is one of the most important risk factors for ET, the genetic causes of ET remain unknown. In an attempt to identify genetic causes for ET, we performed whole-exome sequencing analyses in a large Spanish family with ET, in which two patients also developed e...

BACKGROUND A family with a complicated constellation of neurologic findings, including neuropathy, myotonia, and periodic paralysis, has been described in 4 studies in the medical literature since 1934. The underlying cause of their disease has been the subject of considerable speculation and has never been identified until now. OBJECTIVE To identify the molecular basis of this family's neuro...

Generalized epilepsy with febrile seizures-plus (GEFS) is a benign Mendelian syndrome characterized by childhood-onset febrile and afebrile seizures. Three point mutations within two voltage-gated sodium channel genes have been identi®ed so far: in GEFS type 1 a mutation in the b1-subunit gene SCN1B, and in GEFS type 2 two mutations within the neuronal a-subunit gene SCN1A. Functional expressio...

Generalized epilepsy with febrile seizures plus (GEFS+) is a benign epileptic syndrome of humans. It is characterized by febrile and afebrile generalized seizures that occur predominantly in childhood and respond well to standard antiepileptic therapy. A mutation in the b1-subunit of the voltage-gated sodium channel, linked to chromosome 19q13 (GEFS+ type 1) has been found in one family. For fo...

Hypokalemic periodic paralysis (HypoPP) is an autosomal dominant disorder characterized by episodic attacks of muscle weakness associated with a decrease in blood potassium levels. Recently, mutations in the gene coding for the skeletal muscle voltage-gated sodium channel alpha subunit (SCN4A) have been reported. We detected the R672H mutation in one HypoPP Turkish family.

Generalized epilepsy with febrile seizures-plus (GEFS+) is a benign Mendelian syndrome characterized by childhood-onset febrile and afebrile seizures. Three point mutations within two voltage-gated sodium channel genes have been identified so far: in GEFS+ type 1 a mutation in the beta1-subunit gene SCN1B, and in GEFS+ type 2 two mutations within the neuronal alpha-subunit gene SCN1A. Functiona...