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. |
