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HD Glossary

Here at HD Reach, we have created a glossary to help you navigate the world of Huntington's disease. This glossary is not all-inclusive, but we think it contains the most pertinent information.

A2A adenosine receptor considered to affect the age of onset of HD. It is currently being studied as a target for HD drugs.
Abnormal gene mutated gene.
Abnormal movements movements not typical of an individual such as chorea, dystonia, and unusual eye movement.
Affidavit written statement sworn to be true and used for evidence in court.
Affirmations positive statements that provide emotional support.
Aggression forceful action or hostile behavior without provocation.
Agitation state of restlessness, anxiety, or excitement.
Agnosia loss of ability to recognize objects or persons.
Amniocentesis prenatal sampling of amniotic fluid to test for abnormalities in development.
Ancillary professionals healthcare services that support the primary physician such as speech therapist, occupational therapist, or physical therapist.
Anger an elevated emotional state which can be a healthy, natural response to a threat.
Anxiety a general term that encompasses many psychiatric disorders that stem from extreme fear or worry.
Apathy indifference; suppression of interest, enthusiasm, or concern.
Apoptosis programmed cell death to assist in development.
Apraxia neurological disorder caused by damage to the brain in which an individual cannot carry out certain physical movements even though they desire to.
Arrhythmic without rhythm.
Aspiration pneumonia breathing condition caused by pulmonary aspiration.
Aspiration (1) breathing in a foreign object such as food. (2) medical procedure involved in removing something from the body.
Athetosis condition causing abnormal muscle contractions resulting in involuntary writhing movements.
Autosomal dominant Only on copy of the gene is needed. Huntington’s disease is an autosomal dominant disorder. Children of someone who has Huntington’s disease have a 50% chance of inheriting the gene and the disease.
Basal ganglia area of the brain that is targeted by Huntington’s disease. Location of nerves used for coordinated movements.
Behavior Huntington’s disease can greatly affect an individual’s behavior. Huntington’s disease can cause an increase in risky behaviors, irritability, and aggression.
Binding genetic process of attaching to proteins.
Bipolar disorder mental health disorder that affects mood, energy, and activity levels.
Bolus the administration of medicine or food all at once.
Bradykinesia slow movements.
Cadence the number of steps one foot takes in a minute.
CAG trinucleotide repeat genetic disorder responsible for causing Huntington’s disease.
Chorea involuntary movements that can affect speech, swallowing, posture and gait.
Chromosomal disorders genetic disorders caused by either an abnormal number of chromosomes or an abnormality within the chromosomes.
Chromosome 4 the location of the Huntington gene.
Chromosome structure found in most cells that carry genes.
Chorionic villus sampling (CVS) early pregnancy test used to test if the fetus has inherited Huntington's disease.
Clinical symptoms the observed symptoms of a patient.
Clinical trial research studies that unveil new treatments, discover ways to detect diseases earlier, and assist in daily struggles of those with long-term illnesses.
Clonus uncontrolled, rhythmic muscle contractions caused by a neurological condition.
Cognition the process of gaining and retaining knowledge.
Cognitive Behavioral Therapy (CBT) psychological treatment with the goal of altering one’s mindset to view situations positively and respond more effectively.
Cognitive impairments when an individual struggles to concentrate, remember, make decisions, or learn new things.
Complex disorders disorders that are caused by both genetic and environmental factors. Genes pose a risk but other factors such as lifestyle and environment also play a role. Diabetes is a complex disorder. Also known as multifactorial disorders.
Confirmatory testing typically performed after an analysis. They are used to confirm a diagnosis.
Cytogenetic location the specific location of a gene on a chromosome determined by the pattern of bands that appear after the chromosome has been stained.
Degeneration deterioration.
Depression mood disorder that elevates the feeling of sadness or disinterest.
Disinhibition loss of inhibition.
Distal away from the center of the body.
DNA deoxyribonucleic acid. Genetic information for all living beings.
Dysarthria slow speech caused by muscle weakness.
Dysphagia difficulty swallowing
Dysphoria dissatisfaction with life
Dystonia the uncontrollable contraction of muscles that results in repetitive movements. Movements include cramping of the foot, uncontrollable blinking, and speech difficulties.
Empathy the ability to understand and share the feelings of another.
ENROLL an observational study for families with Huntington's disease.
Epidemiology study of the distribution of diseases throughout a population.
Excitotoxins chemicals that overstimulates and exhausts neuron receptors.
Expansion (genetic) when a cluster of genes becomes bigger through insertion or repetition of nucleotides. Huntington's disease is caused by the expansion of the CAG nucleotide.
Family Safety Plan strategies to ensure the safety of the individual with Huntington’s disease and their family. This may include emergency contacts, location of emergency services, and procedures for dealing with aggression.
GABA Gamma-Amino Butyric acid. the decrease of GABA results in chorea.
Gene unit of heredity, found on chromosome, made up DNA.
Gene expression process from genetic instruction to products.
Gene negative results The abnormal Huntington gene is not present.
Gene positive results The abnormal Huntington gene is present.
Genetic counselor specialized professional trained in assisting families with genetic medical conditions.
Genetic disorder disease caused by a change in the DNA sequences of genes. There are three groups of genetic disorders: single-gene, chromosomal, and complex/multi-factorial.
Genetic transmission the transfer of genetic information from one generation to the next.
Geriatric psychiatrist trained medical professionals who assist the elderly suffering from emotional and mental issues.
HD Buzz website dedicated to the communication of the latest Huntington's disease research to the public.
HD Clarity study aiming to research the cerebrospinal fluid of individuals with Huntington’s disease.
HD Drug Works website which reports the latest information on drug and treatment options for Huntington's disease.
HD Trialfinder tool that uses an individual’s profile to find open studies and trials to join.
HDSA Huntington's Disease Society of America.
Heredity passing on of physical or mental characteristics genetically from one generation to another.
HTT gene gene that causes the production of the huntingtin protein.
Huntingtin protein a protein that appears to affect neurons and development however its exact function is not known.
Huntington gene a gene located in everybody. The Huntington gene will only cause Huntington's disease if an abnormal copy is passed on.
Huntington’s Disease single-gene disorder that causes chorea, dystonia, and loss of cognition.
Huntington's disease single-gene disorder that causes chorea, dystonia, and loss of cognition.
Hyperkinesia increased muscle activity, excessive movements both abnormal and normal.
Hypermetria when movements overshoot the intended goal.
Hypertonia so much muscle tone that it becomes difficult to move.
Hypomimia reduced degree of facial expression.
iCare five strategies for dealing with uncontrolled emotions of behavior: ignore the behavior, change strategies, avoid triggers, redirection, and excuses.
In vitro fertilization (IVF) fertilizing the egg outside the womb and then transferring the embryo to the uterus.
Irritability easily frustrated, upset, or agitated.
Juvenile Huntington’s disease Huntington’s disease that begins to affect an individual before they reach 20 years of age.
LEGATO-HD Trial study investigating how the drug Laquinimod may affect individuals with Huntington’s disease.
Long-term care services to assist in everyday tasks and activities such as care homes, nursing homes, or in-home care.
Mania a mental illness which causes prolonged periods of over-activity, delusions, and excitement.
Mental health therapist medical professional dedicated to helping patients experiencing psychological distress.
Motor impersistance inability to sustain some voluntary movements such as keeping eyes closed.
Motor symptoms symptoms of Huntington's disease that involve movements of the body.
Mutation a change in DNA that is the results of biological and/or environmental factors.
Neurologist doctor specializing in the nervous system.
Neurons nerve cells.
Neuropsychiatrist medical professional dedicated to treating medical issues which cause behavioral, psychological, and psychiatric symptoms.
Neuropsychologists specialist who focuses on the functions of the brain.
Nucleotide building block of DNA and RNA.
Obsessive-compulsive disorders long-lasting mental health disorder which causes reoccurring and unwanted thoughts that produce repetitive behaviors.
Occupational therapist therapist dedicating to helping patients achieve a satisfied state of being.
Pathphysiology the disordered physiological processes associated with disease or injury.
prefrontal cortex area of the brain that is involved in cognitive behavior, personality expression, decision making, and moderating social behavior.
Pre-implantation Genetic Diagnosis (PGD) a procedure occurring after in vitro fertilization but before implantation of the embryo in the uterus to identify genetic defects.
Pre-symptomatic testing tests to determine the presence of a genetic disorder before symptoms begin to appear. These tests are usually performed when a family member has a genetic disorder.
Prevalence proportion of people who have or are at risk of Huntington’s disease.
Prodromal phase initial phase of Huntington's disease where clinical symptoms have started but motor symptoms have not.
Psychiatric impariments Huntington's disease damages the brain which can lead to a decline in mental health. Depression, irritability, and apathy are a few impairments that Huntington's disease can cause.
Psychiatric symptoms symptoms regarding the mental health of the patient.
Psychosis a symptom characterized by disruptions to a person's thoughts and perceptions that make it difficult to recognize what is real and what is not.
Pulmonary aspiration inhalation of foreign objects into the lungs.
Risky Behaviors behaviors that impact the safety of the patient.
RNA ribonucleic acid; carries instructions from DNA to create proteins.
Saccades fast eye movement between one focal point to another.
Share the Care not-for-profit organization dedicated to helping those who are caregivers.
SIGNAL Trial study testing the drug VX15 in early stages of Huntington’s disease.
Single-gene disorders genetic disorder caused by only one gene. Huntington’s Disease is a single-gene disorder.
Social Security Disability a program that pays monthly benefits to you if you become disabled before retirement age and aren’t able to work.
Social workers broad term encompassing professionals dedicated to assisting individual’s in their lives and communities.
Spasmodic action sudden movement usually caused by the contraction of a muscle.
Special care dentist dentists dedicated to assisting individuals with medical issues. They develop a comprehensive plan based on an individual’s medical history.
Speech therapist professional dedicated to assisting individuals with speech, language, and other communication aspects.
Stage 1 The early stage where the patient has received a diagnosis but is still full functional and independent.
Stage 2 The early intermediate stage where the patient is still functional but at a lower capacity. Some assistance with basic function may be required.
Stage 3 Late intermediate stage where the patient can no longer work or manage household responsibilities. Psychiatric and behavioral symptoms may become evident.
Stage 4 The early advanced stage where the patient is not independent but can still live at home with the help of others. Assistance is needed to act on many activities.
Stage 5 The advanced stage where the patient requires complete and total support from professionals.
Subthalamic nucleus (STN) part of the brain involved in action suppression. In Huntington’s disease, action suppression can be impaired.
Sydenham’s chorea disorder that causes jerky movements in the face, hands, and feet.
Symptomatic relief relief from the symptoms of a medical issue but not a cure.
Tardive dyskinesia (TD) side effect of some mental illness medications which cause uncontrolled, jerky movements.
Visuospatial abilities cognitive process needed to determine structure and spatial relations.
WAVE-PREcision HD study dedicated to testing the drug WVE- 120101 and its affect on Huntington’s disease.
Westphal variant a variation of Huntington’s disease which causes juvenile onset of HD.