Idiopathic generalized epilepsy (IGE) is a group of epileptic

Epilepsy

Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...

 disorders that are believed to have a strong underlying genetic basis. Patients with an IGE subtype are typically otherwise normal and have no anatomical brain abnormalities. Patients also often have a family history of epilepsy

Epilepsy

Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...

 and seem to have a genetically predisposed risk of attack. IGE tends to manifest itself between early childhood and adolescence although it can be eventually diagnosed later. The genetic cause of some IGE types is known, though inheritance does not always follow a simple monogenic mechanism.

Benign myoclonic epilepsy in infancy

This form of epilepsy is very rare, representing less than 1% of cases, and is twice as prevalent in boys compared to girls. Age of seizure onset is between 5 months and 5 years of age. Children with this disorder often present with head drops and brief arm jerks. Although there is believed to be a genetic basis for this disorder, no genetic linkage has been shown.

Generalized epilepsy with febrile seizures plus

Generalized epilepsy with febrile seizures plus (GEFS+) is an umbrella for many other syndromes that share causative genes. Patients experience febrile seizure

Febrile seizure

A febrile seizure, also known as a fever fit or febrile convulsion, is a convulsion associated with a significant rise in body temperature...

s early in childhood and grow to experience other types of seizures later in life. Known causative genes for GEFS+ are the sodium channel α subunit genes SCN1A and SCN2A and the β subunit gene SCN1B. Mutations in the GABA_A receptor

GABA A receptor

The GABAA receptor is an ionotropic receptor and ligand-gated ion channel. Its endogenous ligand is γ-aminobutyric acid , the major inhibitory neurotransmitter in the central nervous system. Upon activation, the GABAA receptor selectively conducts Cl- through its pore, resulting in...

 γ subunit GABRG1 are also causative for this disorder.

Epilepsy with myoclonic absences

This rare epilepsy has a wide age range of presentation (from the first year of life through the early teens). This epilepsy is characterized by absence seizures concurrent with myoclonic jerks, typically occurring several times daily. The genetics of this disorder have not been delineated. Seizures from this disorder often cease within 5 years.

Epilepsy with myoclonic-astatic seizures

Originally called Doose syndrome, epilepsy with myoclonic-astatic seizures accounts for ~2% of childhood epilepsies. Children with this disorder have incredibly brief (<100ms) myoclonic jerks followed by equally brief loss of muscle tone, sometimes resulting in dangerous falls. Some patients have much longer lasting seizures of this type. Many patients with this disorder also have absence seizures. This is believed to be a polygenic disorder.

Childhood absence epilepsy

Also known as pyknolepsy, childhood absence epilepsy

Childhood absence epilepsy

Childhood absence epilepsy , also known as pyknolepsy, is an idiopathic generalized epilepsy which occurs in otherwise normal children. The age of onset is between 4–10 years with peak age between 5–7 years. Children have absence seizures which although brief , they occur frequently, sometimes in...

 (CAE) represents up to 10% of all childhood epilepsies. It first manifests in childhood between the ages of 4 and 8 as brief periods of unconsciousness (absence). Mutations in the calcium channel

Calcium channel

A Calcium channel is an ion channel which displays selective permeability to calcium ions. It is sometimes synonymous as voltage-dependent calcium channel, although there are also ligand-gated calcium channels.-Comparison tables:...

 α subunit encoding gene CACNA1H and the GABA receptor

GABA receptor

The GABA receptors are a class of receptors that respond to the neurotransmitter gamma-aminobutyric acid , the chief inhibitory neurotransmitter in the vertebrate central nervous system...

 γ subunit encoding gene GABRG2 yield susceptibility for CAE.

Juvenile absence epilepsy

Juvenile absence epilepsy is similar to CAE but has an onset between ages 9 and 13. Other differences are that patients with this disorder have less frequent but longer absence seizures than those with CAE. There are a number of possible genetic loci for this disorder, though no causative genes have been demonstrated.

Juvenile myoclonic epilepsy

Also known as Janz syndrome, juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy , also known as Janz syndrome, is a fairly common form of idiopathic generalized epilepsy, representing 5-10% of all epilepsies. This disorder typically first manifests itself between the ages of 12 and 18 with myoclonus occurring early in the morning. Most patients also...

 (JME) is a common form of epilepsy, accounting for ~10% of all cases and ~25% of cases of idiopathic generalized epilepsies. Many children with CAE

Childhood absence epilepsy

Childhood absence epilepsy , also known as pyknolepsy, is an idiopathic generalized epilepsy which occurs in otherwise normal children. The age of onset is between 4–10 years with peak age between 5–7 years. Children have absence seizures which although brief , they occur frequently, sometimes in...

 go onto to develop JME. JME first presents between the ages of 12 and 18 with prominent myoclonic seizures. These seizures tend to occur early in the morning. Patients with JME may also have generalized tonic-clonic seizures and absence seizures. Linkage of this disorder has been shown to mutations in the genes GABRA1

GABA receptor

The GABA receptors are a class of receptors that respond to the neurotransmitter gamma-aminobutyric acid , the chief inhibitory neurotransmitter in the vertebrate central nervous system...

, CACNB4

Calcium channel

A Calcium channel is an ion channel which displays selective permeability to calcium ions. It is sometimes synonymous as voltage-dependent calcium channel, although there are also ligand-gated calcium channels.-Comparison tables:...

, CLCN2

Chloride channel

Chloride channels are a superfamily of poorly understood ion channels consisting of approximately 13 members.Chloride channels display a variety of important physiological and cellular roles that include regulation of pH, volume homeostasis, organic solute transport, cell migration, cell...

, GABRD2

GABA receptor

The GABA receptors are a class of receptors that respond to the neurotransmitter gamma-aminobutyric acid , the chief inhibitory neurotransmitter in the vertebrate central nervous system...

and EFHC1.

Epilepsy with generalized tonic-clonic seizures only

This type of IGE can present at almost any age and is poorly characterized. Because of its loose definition, it is impossible to supply an accurate estimate of its prevalence. As implied by its name, patients with this disorder present only with tonic-clonic seizures.