Glossary

A

Absence Seizures

Brief periods (usually 10–20 seconds) where a person stops their activity with a vacant stare. May include eye fluttering or atypical movements. (Epilepsy Foundation)

Antiepileptic Drugs (AED)

Medications used to suppress seizures, also called anticonvulsants. (Epilepsy Foundation)

Antisense Oligonucleotides (ASO)

A genetic therapy that alters mRNA expression in cells.

Atonic Seizure

A “drop attack” where a person loses muscle tone, usually lasting under 15 seconds. (Epilepsy Foundation)

Autism

A developmental disorder affecting communication and behaviour, screened and diagnosed by a healthcare provider. Also known as Autism Spectrum Disorder (ASD). (NIMH / NIH)

C

Cerebral Palsy (CP)

A group of neurological disorders caused by brain damage that affect movement, balance and posture. (NINDS / NIH)

Chromosome

A structure that organises genetic material. Humans have 23 pairs (numbered 1–22, plus X and Y).

Clinical Trials

Research studies that evaluate tests or treatments in people.

D

Deletion Mutation

A mutation that removes genetic material from a gene, including the deletion of an entire gene.

Deoxyribonucleic Acid (DNA)

The basic unit storing genetic information, made of four nucleic acids (A, C, G, T) that form base pairs.

De novo

A new mutation that is not inherited across generations.

Duplication Mutation

A mutation that adds genetic material to a gene.

E

Electroencephalogram (EEG)

A diagnostic test that measures the brain’s electrical activity.

Electrical Status Epilepticus of Sleep (ESES)

A rare syndrome with a characteristic EEG pattern during sleep. Also called epileptic encephalopathy with continuous spike and wave during sleep (CSWS). (Epilepsy Foundation)

Encephalopathy

A disease of the brain.

Epilepsy

A neurological disorder characterised by recurrent seizures that affects the nervous system.

Epilepsy Panel

A genetic test that analyses multiple epilepsy-associated genes simultaneously.

Exon

A segment of DNA that codes for a gene or part of a gene.

F

Febrile Seizure

A seizure associated with a high fever in children. (Epilepsy Foundation)

Focal Seizures

Partial seizures starting in one area or network on one side of the brain. They occur with or without loss of consciousness and are categorised as simple, complex, or secondary generalised. (Epilepsy Foundation)

G

Gene

The basic unit of heredity, made of DNA, that provides instructions for producing proteins. (NIH / MedlinePlus)

Genome

The complete set of genetic material, including the 23 chromosome pairs and mitochondrial DNA. (NIH / National Human Genome Research Institute)

Genetic Disorder

A disease caused by gene changes that alter or prevent protein production. (NIH / MedlinePlus)

Gene Variant

A gene mutation that changes the protein produced, potentially causing a genetic disorder.

H

Haploinsufficiency

A condition where one of two gene copies is non-functional or deleted, producing insufficient protein.

Hypotonia

A condition characterised by low muscle tone. (NIH / NINDS)

I

Incidence

A measurement of events (e.g. STXBP1 diagnoses) within a defined time period.

Induced Pluripotent Stem Cells (iPSCs)

Body cells engineered into pluripotent cells capable of becoming other cell types — useful for biological study and drug development.

Infantile Spasms

Also called West Syndrome. Brief episodes of body stiffening or bending (“jackknife seizures”), usually starting within the first year and stopping around age four. (Epilepsy Foundation)

L

Lennox-Gastaut Syndrome (LGS)

A severe form of childhood-onset epilepsy involving multiple seizure types. (Epilepsy Foundation)

M

microRNA

A family of molecules that help cells control the kinds and amounts of proteins through the control of gene expression. (Ohio State University)

Missense Mutation

A base-pair change that alters the DNA-to-mRNA-to-protein translation.

Myoclonic Seizure

Brief, rapid jerking movements, usually occurring on both sides of the body simultaneously. (Epilepsy Foundation)

N

Neurotransmitter

A chemical messenger between neurons, released from the axon terminal into the synaptic cleft and received by a dendrite receptor.

Nonsense Mutation

A mutation that creates a premature stop codon, resulting in an incomplete protein. (NIH / NHGRI)

P

Phenotype

An observable trait. (National Human Genome Research Institute)

Precision Medicine

Personalised medicine that tailors prevention and treatment by considering a person’s genes, environment and lifestyle. (NIH / MedlinePlus)

Prevalence

A measurement of the number of affected people at a particular point in time.

4-Phenylbutyrate (4PB)

A chemical compound used to treat urea cycle disorders. Research shows potential for STXBP1 disorders but requires further human clinical trials.

S

SNARE Proteins

Brain proteins that create a “SNARE complex” involved in the release of neurotransmitters into the synaptic cleft.

Sudden Unexpected Death in Epilepsy (SUDEP)

An unexplained death in a person with epilepsy. It affects more than 1 in 1,000 people annually and is a leading cause of death for those with uncontrolled seizures. (Epilepsy Foundation)

Synapse

A junction between neurons that transmits electrical or chemical signals, including the presynaptic membrane, synaptic cleft and postsynaptic membrane.

Syntaxin Binding Protein‑1 (STXBP1)

A protein necessary for the release of neurotransmitters.

T

Tonic-Clonic Seizure

Formerly known as a Grand Mal seizure. (Epilepsy Foundation)

W

Whole Exome Sequencing

Genetic testing that identifies DNA sequences from the protein-coding regions of the genome.

Whole Genome Sequencing

Genetic testing that sequences the entire genome.

Definitions are drawn from sources including the Epilepsy Foundation, the US National Institutes of Health (NIH), NINDS and the National Human Genome Research Institute. This glossary is general information, not medical advice — always speak with your clinical team about your situation.