Glossary of Terms
A
ADHD (Attention Deficit Hyperactivity Disorder)
A neurodevelopmental condition affecting attention, impulse control, and activity levels. ADHD is highly prevalent in individuals with TSC (30–50%) and forms part of TAND. It may co-exist with epilepsy and intellectual disability, requiring careful management of medications.
AML (Angiomyolipoma)
A benign tumour made up of blood vessels, smooth muscle, and fat, most commonly affecting the kidneys in TSC (70–80% of patients). AMLs can grow and bleed, requiring monitoring or treatment (e.g. mTOR inhibitors or embolisation).
AML (Angiomyolipoma)
🔗 https://www.kidneycareuk.org/about-kidney-health/conditions/angiomyolipoma/
ASD (Autism Spectrum Disorder)
A neurodevelopmental condition affecting communication, behaviour, and social interaction. Up to 69% of individuals with TSC may meet criteria for ASD. Early diagnosis improves outcomes.
🔗 https://tandconsortium.org/
Autosomal Dominant
A genetic inheritance pattern where only one altered copy of a gene (TSC1 or TSC2) is required to cause TSC. Each child of an affected parent has a 50% chance of inheriting the condition.
🔗 https://medlineplus.gov/genetics/understanding/inheritance/inheritancepatterns/
Autosomal (General)
Refers to genes located on non-sex chromosomes, meaning the condition affects males and females equally.
🔗 https://www.genome.gov/genetics-glossary/Autosomal-Dominant-Disorder
B
Benign Tumour
A non-cancerous growth that does not spread but may still cause problems depending on location. In TSC, benign tumours can occur in multiple organs including brain, kidneys, heart, lungs, and skin.
🔗 https://www.nhs.uk/conditions/benign-brain-tumour/
C
Cardiac Rhabdomyoma (cRHM)
A benign tumour of the heart, often detected during pregnancy or infancy. It is one of the earliest indicators of TSC and often regresses naturally over time.
🔗 https://www.tscalliance.org/understanding-tsc/associated-disorders/#cardiac
Cortical Tuber
A disorganised area of brain tissue found in the cerebral cortex. These lesions are strongly associated with epilepsy, developmental delay, and cognitive differences in TSC.
🔗 https://www.epilepsy.com/what-is-epilepsy/related-conditions/tuberous-sclerosis-complex
CT (Computed Tomography)
A type of imaging scan that uses X-rays to create detailed cross-sectional images of the body. Used in TSC surveillance when MRI is not suitable.
🔗 https://www.hse.ie/eng/health/az/c/computed-tomography-ct-scan/
D
Dental Enamel Pits
Small defects in the enamel of teeth commonly seen in individuals with TSC. They are usually harmless but can assist in diagnosis.
🔗 https://www.tscalliance.org/understanding-tsc/associated-disorders/#dental
De Novo Mutation (Sporadic Mutation)
A new genetic mutation occurring for the first time in a child, without being inherited from either parent. Around two-thirds of TSC cases arise this way.
🔗 https://medlineplus.gov/genetics/understanding/mutationsanddisorders/
E
EEG (Electroencephalogram)
A test that measures electrical activity in the brain and is used to diagnose and monitor epilepsy in TSC.
🔗 https://www.epilepsy.ie/content/eeg
Epilepsy
A neurological condition characterised by recurrent seizures. It affects up to 90% of individuals with TSC and is often one of the earliest clinical features.
🔗 https://www.epilepsy.ie/content/tuberous-sclerosis-complex
Everolimus (mTOR Inhibitor)
A targeted therapy used to treat TSC-related tumours (e.g. SEGA, AML) and sometimes epilepsy by inhibiting the mTOR pathway.
🔗 https://www.ema.europa.eu/en/medicines/human/EPAR/votubia
H
Hamartoma
A benign, tumour-like growth made up of disorganised but normal tissue elements. TSC is characterised by widespread hamartomas.
🔗 https://rarediseases.org/rare-diseases/tuberous-sclerosis/
Hamartin–Tuberin Complex
Proteins produced by the TSC1 and TSC2 genes that regulate cell growth via the mTOR pathway. Dysfunction leads to uncontrolled growth and tumour formation.
🔗 https://www.nature.com/subjects/mtor-signaling
Hydrocephalus
A build-up of cerebrospinal fluid in the brain, often caused by a SEGA blocking fluid pathways, requiring urgent treatment.
🔗 https://www.nhs.uk/conditions/hydrocephalus/
I
Infantile Spasms (IS)
A severe form of epilepsy occurring in infancy, commonly associated with TSC. Early treatment (often with vigabatrin) is critical.
🔗 https://www.epilepsy.ie/content/infantile-spasms
Intellectual Disability (ID)
A condition involving limitations in intellectual functioning and adaptive behaviour. It can range from mild to severe in TSC.
🔗 https://www.hse.ie/eng/services/list/4/disability/
L
LAM (Lymphangioleiomyomatosis)
A progressive lung disease affecting mainly women with TSC, caused by abnormal smooth muscle cell growth in the lungs.
🔗 https://www.europeanlung.org/en/information-hub/lung-conditions/lymphangioleiomyomatosis/
M
MRI (Magnetic Resonance Imaging)
A detailed imaging technique using magnetic fields to visualise internal organs, particularly important for brain and kidney monitoring in TSC.
🔗 https://www.hse.ie/eng/health/az/m/mri-scan/
mTOR Pathway
A cellular signalling pathway that regulates growth and metabolism. Overactivation due to TSC mutations leads to tumour formation.
🔗 https://www.nature.com/subjects/mtor-signaling
mTOR Inhibitors (Rapalogs)
Medications such as everolimus and sirolimus that suppress abnormal cell growth in TSC by targeting the mTOR pathway.
Multidisciplinary Team (MDT)
A coordinated group of specialists (neurology, nephrology, dermatology, psychiatry, etc.) providing comprehensive TSC care.
🔗 https://www.hse.ie/eng/about/who/cspd/ncps/mdt/
P
Phakomatosis
A group of genetic disorders (including TSC) characterised by abnormalities in the skin, brain, and eyes.
🔗 https://www.ncbi.nlm.nih.gov/books/NBK560728/
R
Retinal Hamartoma (Phakoma)
A benign tumour on the retina that may affect vision but is often asymptomatic.
🔗 https://www.aao.org/eye-health/diseases/retinal-hamartoma
Renal (Kidney-related)
Refers to the kidneys. Renal complications such as AML are a major concern in TSC.
🔗 https://www.hse.ie/eng/health/az/k/kidney-disease/
S
SEGA (Subependymal Giant Cell Astrocytoma)
A slow-growing brain tumour that can block cerebrospinal fluid flow and cause hydrocephalus. Requires monitoring and sometimes surgery or medication.
🔗 https://www.tscalliance.org/understanding-tsc/associated-disorders/#sega
SEN (Subependymal Nodule)
Small benign growths along the brain ventricles that may develop into SEGA.
Seizure
A sudden burst of abnormal electrical activity in the brain. Seizure types vary widely in TSC.
🔗 https://www.epilepsy.ie/content/seizures
Shagreen Patch
A thickened, leathery patch of skin, typically found on the lower back. A classic dermatological sign of TSC.
Surveillance
Lifelong monitoring using imaging and clinical review to detect complications early and guide treatment.
🔗 https://www.tscalliance.org/resources/tsc-diagnostic-criteria-surveillance-and-management-guidelines/
T
TAND (TSC-Associated Neuropsychiatric Disorders)
An umbrella term covering cognitive, behavioural, psychiatric, academic, and psychosocial difficulties experienced by up to 90% of individuals with TSC.
🔗 https://tandconsortium.org/
TSC (Tuberous Sclerosis Complex)
A rare, multisystem genetic condition caused by mutations in TSC1 or TSC2, leading to benign tumours in multiple organs.
🔗 https://www.orpha.net/en/disease/detail/805
TSC1 Gene
Located on chromosome 9, this gene produces hamartin, a protein that regulates cell growth.
TSC2 Gene
Located on chromosome 16, this gene produces tuberin, which works with hamartin to suppress tumour formation.
U
Ungual Fibroma (Koenen’s Tumour)
Small benign growths around or under fingernails or toenails, often appearing in adolescence or adulthood.
V
Variable Expressivity
The degree to which TSC symptoms vary between individuals, even within the same family.
Vigabatrin
A first-line anti-seizure medication used particularly for infantile spasms in TSC.
🔗 https://www.hpra.ie/homepage/medicines
Clinical & Medical
EEG – Electroencephalogram
MRI – Magnetic Resonance Imaging
CT – Computed Tomography
AML – Angiomyolipoma
SEGA – Subependymal Giant Cell Astrocytoma
SEN – Subependymal Nodule
LAM – Lymphangioleiomyomatosis
TSC-Specific
TSC – Tuberous Sclerosis Complex
TAND – TSC-Associated Neuropsychiatric Disorders
TAND-L / TAND-SQ – TAND tools
Irish Healthcare Context
HSE – Health Service Executive
GP – General Practitioner
CAMHS – Child & Adolescent Mental Health Services
Research & Policy
ERN – European Reference Networks
IRDiRC – International Rare Disease Research Consortium
HRB – Health Research Board