Amino acid: a type of compound that is the building block of proteins.

Athetosis: a condition in which abnormal muscle contraction causes involuntary writhing movements.


Bradyarrythmia: a slow heart rate.

Byproduct: a substance that is created in the process of making something else.


Carer: someone who regularly looks after and provides care or assistance to someone, such as a child, an elderly person, or someone who is sick or disabled.

Cerebral palsy: a disability resulting from damage to the brain before, during, or shortly after birth that causes issues with body movement, muscle tone, speech disturbances, and/or other medical issues.

Cerebrospinal fluid (CSF): the fluid surrounding the brain and spinal cord.

Chorea: a neurological disorder characterised by jerky involuntary movements affecting especially the shoulders, hips and face.

Choreoathetosis: the occurrence of involuntary movements in a combination of chorea (irregular migrating contractions) and athetosis (twisting and writhing).

Clinical Geneticist: a physician who is trained to help identify and study genetic disorders.

Computed tomography (CT): a scan that uses a series of X-ray images taken from different angles around the body and uses computer processing to create a cross-sectional image of the inside of the body.


Deficiency: a lack or shortage of something.

DDC (dopa decarboxylase) gene: a gene that provides instructions for making the enzyme aromatic L-amino acid decarboxylase (AADC), which is important in the brain and nervous system.

Diaphoresis: sweating, especially to an unusual degree as a symptom of disease or a side effect of a drug.

Distal Chorea: non ryhthmic, jerky, rapid involuntary movement of the distal muscles and face.

Diurnal: daily.

Dyskinesia: abnormality or impairment of voluntary movement.

Dysmotility: a variety of symptoms that occur when the gut does not work properly at moving its contents (food, drink, tablets, etc) along.

Dysphonia: difficulty in speaking due to a physical disorder of the mouth, tongue, throat or vocal chords.

Dystonia: uncontrolled and sometimes painful muscle movements (spasms).


Electroencephalography (EEG): a test that looks at abnormalities in the brain by attaching small metal electrodes to the scalp in order to detect tiny electrical charges from brain activity.

Enzyme: a substance that helps to bring about, speed up, or regulate chemical reactions.

Epilepsy: a chronic disorder that causes sudden episodes in which the patient may lose consciousness, have his/her senses disrupted, shake uncontrollably, and/or show other symptoms (for example, seizures or fits); often caused by abnormal electrical activity in the brain.


Flailing: waving or swinging wildly.


Gastroenterologist: a medical professional who specialises in identifying and treating disorders of the stomach and intestines.

General Practitioner: a medical professional who is trained to provide health care to patients of any gender or age.

Genetic: relating to or determined by genes; something that is passed down through families and considered inherited.

Genetic testing: a study of DNA to find differences, abnormalities, or changes that could cause disorders or to determine if a person has or will develop a certain disease.


Hypertonia: spasticity and rigidity due to damage of the central nervous system.

Hypokinesia: decreased spontaneous bodily movement. Characterised by a partial or complete loss of muscle movement.

Hypotension: low blood pressure.

Hypotonia: "floppy baby syndrome". A state of low muscle tone, often involving reduced muscle strength.

Hypotonia: low muscle tone, often involving reduced muscle strength.


Involuntary: done without conscious control.


Lumbar puncture: a medical procedure in which fluid from the spine is removed with a needle; often done for diagnostic testing. Also called a spinal tap.


Magnetic resonance imaging (MRI): a test that uses a magnetic field and radio waves to create detailed images of the body’s organs and structures.

Metabolite: any substance that is made during the changing of one chemical compound into another.

Movement Disorder Specialist: a healthcare professional who has special training in disorders that affect someone’s ability to move, such as Parkinson’s disease, or that involve low muscle tone (hypotonia) or tremors.

Muscle spasm: an uncontrolled tightening of a muscle that can cause a great deal of pain.

Muscle tone: the amount of tension or resistance in a muscle at rest or in response to stretching.

Mutation: a change that happens in a gene.

Myoclonus: spasmodic jerky contraction of groups of muscles.


Nervous system: an organ system of the body made up of the brain, spinal cord, and nerves.

Neurological: relating to the makeup, functions, and disorders of the nervous system.

Neuromuscular: relating to nerves and muscles.

Neurotransmitter: a chemical substance that works as a messenger to send signals from one nerve cell to another.


Occupational Therapist: a healthcare professional who works to help mentally, physically, and developmentally disabled patients improve their ability to participate in everyday activities.

Oculogyric crises: periods of involuntary eye movements during which the eyes suddenly roll upward involuntarily; can last anywhere from a few seconds to hours, and can happen several times a day or several times a week.


Parkinsonism: a clinical syndrome characterised by tremor, bradykinesia, rigidity and postural instability.

Paediatrician: a medical professional who specialises in the development, care, and treatment of children and their diseases.

Paediatric Neurologist: a medical professional who focuses on studying and treating diseases and conditions that affect the nervous system of children.

Physical Therapist: a trained healthcare professional who helps patients reduce pain and strengthen muscles to improve mobility.

Plasma: the colourless fluid part of blood.

Precursor: a substance from which another substance is created.

Ptosis: a drooping or falling of the upper eyelid. 


Reflux: to flow backward in the body, such as from the stomach.


Seizure: a sudden attack, spasm, or convulsion, as in epilepsy or another disorder.

Spasm: a sudden involuntary muscular contraction or convulsive movement.

Speech Therapist: a healthcare professional who specialises in the treatment of speech and communication disorders.

Stimulus: a thing or event that evokes a specific functional reaction in an organ or tissue.

Symptom: an indication of a disease or a change in a condition that the patient notices.


Tremor: an involuntary, somewhat rhythmic, muscle contraction and relaxation involving oscillations or twitching movements of one or more body parts.


quick links

stay in touch

find us

  • Grey LinkedIn Icon
  • Grey Facebook Icon
  • Grey Twitter Icon
  • Grey YouTube Icon
  • Grey Instagram Icon


To contact us please email via: and we will endeavour to reply to you as soon as possible. We apologise in advance for any delays in our response, during this time. Our staff are on furlough and working from home. Please bear with us. Thank you for your patience.


The AADC Research Trust

Soper Hall, 2 Harestone Valley Road,

Caterham, Surrey, CR3 6HY

Registered Charity

UK & Wales No: 1114367

© AADC Research Trust