Primary hypokalemic periodic paralysis (HOKPP) is an autosomal dominant disorder manifesting as recurrent periodic flaccid paralysis and concomitant hypokalemia. HOKPP is divided into type 1 and type 2 based on the causative gene. Although 2 different ion channels have been identified as the molecular genetic cause of HOKPP, the clinical manifestations between the 2 groups are similar. We repor...

Hypokalaemic periodic paralysis (hypoPP) is an autosomal dominant muscle disorder characterized by episodic attacks of muscle weakness associated with a decrease in blood potassium levels. Mutations in the gene encoding the skeletal muscle voltage-gated calcium channel alpha-1 subunit (CACNL1A3) account for the majority of cases. Recently, mutations in the gene coding for the skeletal muscle vo...

Laryngospasm is a rare but potentially life-threatening occurrence in infants and usually has infective, allergic, metabolic, or anatomic causes. Underlying genetic conditions are rarely considered. Mutations in SCN4A encoding the voltage-gated sodium channel NaV1.4 have been implicated in a wide spectrum of neuromuscular disorders with variable onset, ranging from a rare form of congenital mya...

www.thelancet.com Published online March 28, 2018 http://dx.doi.org/10.1016/S0140-6736(18)30477-X 1 Sudden infant death syndrome (SIDS) remains a leading cause of infant mortality, despite a steadily decreasing incidence since the 1990s. The reasons for this decline are debated, but it could be due to methodological reasons (eg, changes in reporting or advances in diagnosis of specific diseases...

Mutations of skeletal muscle sodium channel a subunit (SCN4A) gene are associated with a group of allelic diseases, including periodic paralysis, paramyotonia congenital, sodium channel myotonia, and congenital myasthenic syndrome. Periodic paralysis is characterized by episodic attacks of flaccid weakness with the fluctuation of serum potassium, which are usually limited to skeletal muscles ow...

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...