We have collated a ‘Glossary for Families’ to explain terms used frequently within the Syngap community. The definitions are intentionally in layman’s terms and are what we wish we understood at the beginning of our Syngap journeys. We hope they help you too.

General terms:

Atypical: Being outside of a type, group or class.

Neurotypical: a term used for people who develop typically without issues.

Syngap: Syngap is a protein which in humans is encoded by the SYNGAP1 gene. Mutations in the Syngap1 gene result in a condition called Syngap.

Syngapian: Affectionately used by families when talking about their family member with Syngap.

Genetics:

Chromosome: An organised structure of DNA containing many genes that is wrapped around proteins found in cells. Humans typically have 23 pairs of chromosomes or 46 total.

Deletion: Where the mutation involves the loss of genetic material.

De novo: a genetic mutation that is present for the first time in a family, typically not inherited.

Duplication: When an extra copy of a gene is made in a organism’s genome.

Exon: A section of DNA that serves as the set of instructions for constructing a protein. The Syngap1 gene has 19 exons.

Genome: The complete DNA sequence in the chromosomes of an individual.

Heterozygous: Refers to having two different versions of a gene. Syngap is thought of heterozygous as one copy of the gene functions normally while the other copy has a mutation leading to dysfunction.

Haploinsufficient: When you have one functioning copy of the gene and one which doesn’t produce enough of the protein for normal function.

Missense mutation: A point mutation resulting in a single nucleotide change and consequently a different amino acid. The amino acid change then changes the role of protein in the cell.

Mosaicism: the presence of two or more chromosome patterns in the cells of a person, resulting in two or more cell lines (i.e., some with 46 chromosomes, others with 47)

Think of it like patches of the mutation occurring in an otherwise healthy pool of genes. Some people have mosaicism in their normal cells (somatic cells) so this may be picked up in a blood test while others have mosaicism in their reproductive cells (gonadal cells) leading to germline mosaicism. Germline mosaicism can only be identified in a parent by testing their reproductive eggs or sperm cells.

Mutation: A change that occurs in a gene.

Nonsense mutation: A point mutation in the gene which resulting in a premature stop,  resulting in a shortened (truncated) protein.

Pathogenic: Causing disease.

Phenotype: An individual’s observable characteristics or traits.

Protein: Proteins make up many parts of every cell in the body. Proteins are made up of amino acids and the order of those amino acids determines what form and role a protein has. Syngap is a protein (see Syngap definition).

Genetic 101:

Characteristics common to syngapians:

ASD: Autism Spectrum Disorder

Ataxic: Impaired coordination

Apraxia: A motor speech disorder that makes it difficult to speak/form words.

Cortical Visual Impairment: Most common cause of permanent visual impairment in children. Is characterised by (among other things) an unusual response to light and brief fixations and intermittent following.

Echolalia: When a person repeats words or sentences.

Gait: how a person walks. Gait abnormalities are common in syngapians.

Hypotonia: Weak muscle tone

ID: Intellectual disability.

Nystagmus: An involuntary eye movement which may cause the eye to move rapidly.

Poor proprioception: Lack of awareness of the movement of the body and its position in its environment.

Spasticity: A condition where muscles stiffen or tighten, preventing normal fluid movement.

Common symptoms graphed:

Access full paper HERE

Seizure types common in syngapians:

Absence: a type of seizure that involves brief, sudden lapses in attention. Can look like they’re staring,  like the person has ‘checked out’ for the seizure duration. Very common in syngapians. Also known as petit mal seizures.

Atonic: also known as ‘drop’ seizures, where muscles lose their tone resulting in the person dropping to the ground if they were standing. Common in syngapians.

Epileptic encephalopathy: Seizures that are usually multiform and intractable. 95% of syngapians have seizures, has to impact development.

Eyelid myoclonia: brief and repeated fluttering of the eyelids, often with eyeballs rolling upwards. Very common in syngapians, especially when eating.

Myoclonic: brief shock-like uncontrolled jerks. The person is usually awake and conscious. Common in syngapians.

Refractory epilepsy: Seizures that are unable to be controlled with medications.

Tonic clonic: the ‘movie’ seizure. Loss of consciousness, jerky movements and muscles stiffen. Lasts for minutes and often takes the person an hour or more to fully recover. Not overly common in syngapians but can happen.

Common Epilepsy Medications:

AED: Anti-epileptic drugs

Carbamazepine: (Tegretol).

CBD/Cannabidiol: A chemical compound made from marijuana and hemp. Available in both pharmaceutical grade and naturceutical grade. Does not have THC.

Clobazam: A benzodiazepine, popular anti-epileptic med. Also known as Onfi.

Clonazepam: (Rivotril) also popular among sygapians to help control epilepsy.

Ethosuximide: (Zaronitn) A medication used to treat absence seizures. Can be used with a secondary AED such as valporic acid.

Lamotrigine: (Lamictal) incredibly popular anti epilepsy drug with syngapians.

Levetiracetam: (Keppra) Common anti-epileptic med. Some Syngapiens have gotten ‘Keppra Rage‘.

Sodium Valproate: (Epilim) some syngapians have success with sodium valproate but others have had base experiences with it.

THC: The part of cannabis that gets you stoned. Often added in small doses to CBD to get better seizure control.

Topiramate: (Topamax) An anti-epileptic med.

Zonisamide: Another AED. Chemically it is a sulfonamide.

Common Behaviour Medications:

Clonidine: (Catapres).

Guanfacine: Non-stimulant medication, used in treating ADHD.

Rispiardone: (Risperdal) An atypical antipsychotic.

Zoloft: Antidepressant.

Diet:

Ketogenic diet (keto): A diet designed to help prevent seizures. It is quite complicated and difficult to follow but some syngapians have great success.

Modified Atkins diet (MAD): A lesser version of the ketogenic diet which has also offered some syngapians success in reducing seizures.

Net carbs: Carbs that are absorbed by the body that are limited in both the keto and MAD diets.

Therapy/therapy supports:

AAC: Augmentative and alternative communication. Methods used to supplement or replace speech or writing.

ABA: Applied behavioural analysis. A popular therapy (especially in the USA) that aims to improve behaviours through positive reinforcement.

OT: Occupational therapy. Focuses on helping people access their occupation so for children this involves lots of play activities and self care activities like feeding and dressing.

PECS cards: Picture exchange communication system is a popular AAC that uses pictures to communicate.

PT: Physiotherapy. Helps improvement movement, strength and flexibility and to relieve pain.

Speech therapy: Helps build communication through multiple ways including speech, sign, AAC and PEC cards.

Orthotics/AFO/SMO: Custom made functional foot devices that provide accurate support and help maintain posture. Orthotics are in shoe supports, AFO’s (ankle support foot orthotics) and SMO’s support the ankle as well as the foot sole and look a little bit like a boot.

Medical:

EEG: A test that detects seizure activity using small metal disks attached to the scalp. Full name is an electroencephalogram.

Titrate: continuously adjust the medication dose to get maximum benefit with the least negative side effects possible.

Research:

ASO (antisense oligonucleotides): a precision gene therapy that has had success in finding a cure for others conditions (e.g. Spinraza for SMA).

A great webinar produced by our SCN2A friends interviewing one of the researchers working on an ASO for Syngap, Professor Steve Petrou. https://scn2aaustralia.org/webinar-1/