Down Syndrome Glossary of Terms

Abdominal: Relating to the abdomen, the belly, that part of the body that contains all of the structures between the chest and the pelvis. The abdomen is separated anatomically from the chest by the diaphragm, the powerful muscle spanning the body cavity below the lungs.
See the entire definition of Abdominal

Acute: Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care.
See the entire definition of Acute

ADHD: Attention deficit hyperactivity disorder.

Advanced maternal age: Usually defined as age 35 or more for the mother at the time of delivery of her baby.
See the entire definition of Advanced maternal age

Alzheimer disease: See: Alzheimer's disease.

Alzheimer's disease: A progressive neurologic disease of the brain that leads to the irreversible loss of neurons and dementia. The clinical hallmarks of Alzheimer's disease are progressive impairment in memory, judgment, decision making, orientation to physical surroundings, and language. A working diagnosis of Alzheimer disease is usually made on the basis of the neurologic examination. A definitive diagnosis can be made only at autopsy. On a cellular level, Alzheimer's disease is characterized by unusual helical protein filaments in nerve cells (neurons) of the brain. These odd twisted filaments are called neurofibrillary tangles. On a functional level, there is degeneration of the cortical regions, especially the frontal and temporal lobes, of the brain.
See the entire definition of Alzheimer's disease

Amniocentesis: Procedure used in prenatal diagnosis to obtain amniotic fluid which can be used for genetic and other diagnostic tests. Informally called an "amnio."

Analysis: A psychology term for processes used to gain understanding of complex emotional or behavioral issues.

Anus: The opening of the rectum to the outside of the body.
See the entire definition of Anus

Apnea: An apnea is a period of time during which breathing stops or is markedly reduced. There are two types of apneas, the more common obstructive sleep apnea and the less common central sleep apnea.
See the entire definition of Apnea

Atresia: Absence of a normal opening or failure of a structure to be tubular.
See the entire definition of Atresia

Atrial: Pertaining to the atria, the upper chambers of the heart, as in atrial fibrillation and atrial septal defect.

Autism: A spectrum of neuropsychiatric disorders characterized by deficits in social interaction and communication, and unusual and repetitive behavior. Some, but not all, people with autism are non-verbal.
See the entire definition of Autism

Brain: That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."

Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).
See the entire definition of Cancer

Cardiac: Having to do with the heart.

Cell: The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane.
See the entire definition of Cell

Cerebellum: The portion of the brain in the back of the head between the cerebrum and the brain stem. The cerebellum controls balance for walking and standing and other complex motor functions.

Cervical: Having to do with any kind of neck including the neck on which the head is perched and the neck of the uterus. The word "cervix" in Latin means "neck". That is why cervical vertebrae and cervical cancer involve quite disparate parts of the anatomy joined only by the meaning of the word "cervix".

Chorionic villus sampling: A procedure for first-trimester prenatal diagnosis. Chorionic villus sampling may be done between the eighth and tenth weeks of pregnancy. The aim is to diagnose severe abnormalities afflicting the fetus. In the procedure, tissue is withdrawn from the villi (vascular fingers) of the chorion, a part of the placenta, and examined. Chorionic villus sampling is referred to commonly as CVS.

Chromosome: A visible carrier of the genetic information.
See the entire definition of Chromosome

Chromosomes: The microscopically visible carriers of the genetic material. They are composed of deoxyribonucleic acid (DNA) and proteins and, under a microscope, look like little rods.
See the entire definition of Chromosomes

Clinical trials: Trials to evaluate the effectiveness and safety of medications or medical devices by monitoring their effects on large groups of people.
See the entire definition of Clinical trials

Cognition: The process of knowing and, more precisely, the process of being aware, knowing, thinking, learning and judging. The study of cognition touches on the fields of psychology, linguistics, computer science, neuroscience, mathematics, ethology and philosophy.
See the entire definition of Cognition

Cognitive: Pertaining to cognition, the process of knowing and, more precisely, the process of being aware, knowing, thinking, learning and judging. The study of cognition touches on the fields of psychology, linguistics, computer science, neuroscience, mathematics, ethology and philosophy.
See the entire definition of Cognitive

Conception: 1. The union of the sperm and the ovum. Synonymous with fertilization.
2. The onset of pregnancy, marked by implantation of the blastocyst into the endometrium.
3. A basic understanding of a situation or a principle.
From the Latin conceptio, conceptionis meaning conception, becoming pregnant; drawing up of legal formulae; and from the Latin conceptus meaning conceiving, pregnancy; collecting, or a collection.

Congenital: Present at birth. A condition that is congenital is one that is present at birth. There are numerous uses of "congenital" in medicine. There are, for example, congenital abnormalities. (For more examples, see below.)
See the entire definition of Congenital

Congenital heart disease: A malformation of the heart or the large blood vessels near the heart. The term "congenital" speaks only to time, not to causation; it means "born with" or "present at birth."
See the entire definition of Congenital heart disease

Constipation: Infrequent (and frequently incomplete) bowel movements. The opposite of diarrhea, constipation is commonly caused by irritable bowel syndrome, diverticulosis, and medications (constipation can paradoxically be caused by overuse of laxatives). Colon cancer can narrow the colon and thereby cause constipation. The large bowel (colon) can be visualized by barium enema x-rays, sigmoidoscopy, and colonoscopy. Barring a condition such as cancer, high-fiber diets can frequently relieve the constipation.

Dementia: Significant loss of intellectual abilities such as memory capacity, severe enough to interfere with social or occupational functioning.
See the entire definition of Dementia

Depression: An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression.
See the entire definition of Depression

Diagnosis: 1 The nature of a disease; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies. 3 The identification of any problem. The diagnosis was a plugged IV.
See the entire definition of Diagnosis

Down syndrome: A common chromosome disorder due to an extra chromosome number 21 (trisomy 21). Down syndrome causes mental retardation, a characteristic face, and multiple malformations. Down syndrome is a relatively common birth defect. The chromosome abnormality affects both the physical and intellectual development of the individual.
See the entire definition of Down syndrome

Down syndrome critical region: (Abbreviated DSCR) A region on the long (q) arm of chromosome 21 thought to be responsible for some, if not all, of the features of Down syndrome. A number of genes in this region may be involved in the production of the Down syndrome phenotype.
See the entire definition of Down syndrome critical region

DSCR: See: Down syndrome critical region.

Ductus: A duct or walled passageway suitable for the conveyance of air or, more often in the body, liquids.
See the entire definition of Ductus

Ductus arteriosus: A key arterial shunt (ductus) in fetal life. Before birth, blood pumped from the heart through the pulmonary artery toward the lungs is shunted into the aorta. This arterial shunt is a short vessel called the ductus arteriosus. When the shunt is open, it is said to be patent.
See the entire definition of Ductus arteriosus

Duodenal: Pertaining to the duodenum, part of the small intestine. As in duodenal ulcer or duodenal biliary drainage.

Dysfunction: Difficult function or abnormal function.
See the entire definition of Dysfunction

Ear: The hearing organ. There are three sections of the ear, according to the anatomy textbooks. They are the outer ear (the part we see along the sides of our head behind the temples), the middle ear, and the inner ear. But in terms of function, the ear has four parts: those three and the brain. Hearing thus involves all parts of the ear as well as the auditory cortex of the brain. The external ear helps concentrate the vibrations of air on the ear drum and make it vibrate. These vibrations are transmitted by a chain of little bones in the middle ear to the inner ear. There they stimulate the fibers of the auditory nerve to transmit impulses to the brain.
See the entire definition of Ear

Esophageal: Pertaining to the esophagus.

Father: (1) The male parent. (2) One who originates. For example, "Wilhelm Roentgen is considered the father of radiology." (3) To produce offspring as a male. (4) To provide paternal protection and guidance to children.

Femur: The femur is the bone in the leg that extends from the hip to the knee.
See the entire definition of Femur

Fertile: Able to conceive and bear offspring.

Fertilization: Fertilization is the process of combining the male gamete, or "sperm," with the female gamete, or "ovum." The product of this combination is a cell called a zygote.

Fistula: An abnormal passageway in the body. The fistula may go from the body surface into a blindpouch or into an internal organ or go between two internal organs.
See the entire definition of Fistula

Fluorescent in situ hybridization: An important molecular cytogenetic method for identifying chromosomes and parts of chromosomes, deciphering chromosome rearrangements, and locating genes on chromosomes.
See the entire definition of Fluorescent in situ hybridization

Gastrointestinal: Adjective referring collectively to the stomach and small and large intestines.
See the entire definition of Gastrointestinal

Genes: The basic biological units of heredity. Segments of deoxyribonucleic acid (DNA) needed to contribute to a function.
See the entire definition of Genes

Genetic: Having to do with genes and genetic information.

Genetics: The scientific study of heredity. Genetics pertains to humans and all other organisms. So, for example, there is human genetics, mouse genetics, fruitfly genetics, etc.
See the entire definition of Genetics

Gonadotropin: Hormones that are secreted by the pituitary gland, and that affect the function of the male or female gonads.
See the entire definition of Gonadotropin

Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.
See the entire definition of Heart

Heart disease: Any disorder that affects the heart. Sometimes the term "heart disease" is used narrowly and incorrectly as a synonym for coronary artery disease. Heart disease is synonymous with cardiac disease but not with cardiovascular disease which is any disease of the heart or blood vessels. Among the many types of heart disease, see, for example: Angina; Arrhythmia; Congenital heart disease; Coronary artery disease (CAD); Dilated cardiomyopathy; Heart attack (myocardial infarction); Heart failure; Hypertrophic cardiomyopathy; Mitral regurgitation; Mitral valve prolapse; and Pulmonary stenosis.

Hippocampus: An area buried deep in the forebrain that helps regulate emotion and memory. Functionally, the hippocampus is part of the olfactory cortex, that part of the cerebral cortex essential to the sense of smell. Certain antidepressants (such as fluoxetine, or Prozac) influence the birth of new neurons in the hippocampus. The hippocampus is so-called because its shape suggests that of a seahorse. From the Greek hippos (horse) = kampos (a sea monster).

Human chorionic gonadotropin: (hCG) A human hormone made by chorionic cells in the fetal part of the placenta. Human chorionic gonadotropin (hCG) is directed at the gonads and stimulates them. Hence, the name "gonadotropin."
See the entire definition of Human chorionic gonadotropin

Humerus: The long bone in the arm which extends from the shoulder to the elbow.

Hyperactivity: A higher than normal level of activity. An organ can be described as hyperactive if it is more active than usual. Behavior can also be hyperactive.
See the entire definition of Hyperactivity

Hypothyroid: Deficiency of thyroid hormone which is normally made by the thyroid gland which is located in the front of the neck:

Hypotonia: Decreased tone of skeletal muscles. In a word, floppiness. Hypotonia is a common finding in cerebral palsy and other neuromuscular disorders. Untreated hypotonia can lead to hip dislocation and other problems. Treatment is via physical therapy. In some cases braces may be needed to permit a full range of movement despite hypotonia.

Imperforate anus: A congenital malformation (a birth defect) in which the rectum is a blind alley (a cul-de-sac) and there is no anus.
See the entire definition of Imperforate anus

In situ: In the normal location. An "in situ" tumor is one that is confined to its site of origin and has not invaded neighboring tissue or gone elsewhere in the body.
See the entire definition of In situ

In situ hybridization: The use of a DNA or RNA probe to detect the complementary sequence.
See the entire definition of In situ hybridization

Indicate: In medicine, to make a treatment or procedure advisable because of a particular condition or circumstance. For example, certain medications are indicated for the treatment of hypertension during pregnancy while others are contraindicated.

Infant: A child up to 2 years (24 months) of age.
See the entire definition of Infant

Infantile spasms: A seizure disorder of infancy and early childhood with the onset predominantly in the first year of life of myoclonic seizures, hypsarrhythmia (abnormal, chaotic electroencephalogram), and mental retardation. The spasms are sudden, brief contractions of one or more muscle groups, and may be followed by a longer (less than 10 seconds) tonic phase. Most often the spasms occur in clusters during which the intensity or the frequency of the spasms may increase progressively to a peak, decline, or cease. The clusters tend to occur soon after arousal from sleep. They are not a feature of falling asleep. The spasms usually involve the muscles of the neck, trunk, and extremities.
See the entire definition of Infantile spasms

Inheritance: Not something that is contained in a will, but rather a gene, chromosome or genome that is transmitted from parent to child.
See the entire definition of Inheritance

Intervention: The act of intervening, interfering or interceding with the intent of modifying the outcome. In medicine, an intervention is usually undertaken to help treat or cure a condition. For example, early intervention may help children with autism to speak. "Acupuncture as a therapeutic intervention is widely practiced in the United States," according to the National Institutes of Health. From the Latin intervenire, to come between.

Leg: In popular usage, the leg extends from the top of the thigh down to the foot. However, in medical terminology, the leg refers to the portion of the lower extremity from the knee to the ankle.
See the entire definition of Leg

Leukemia: Cancer of the blood cells. The growth and development of the blood cells are abnormal. Strictly speaking, leukemia should refer only to cancer of the white blood cells (the leukocytes) but in practice it can apply to malignancy of any cellular element in the blood or bone marrow, as in red cell leukemia (erythroleukemia).
See the entire definition of Leukemia

Maternal: 1. Pertaining to the mother as, for example, the maternal mortality rate. 2. Related through the mother as, for example, the maternal grandparents. 3. Inherited from the mother as, for example, the maternal X chromosome.

Maternal age: The age of the mother at the time of delivery. Advanced maternal age is usually defined as age 35 or more at delivery.
See the entire definition of Maternal age

Memory: 1. The ability to recover information about past events or knowledge. 2. The process of recovering information about past events or knowledge. 3. Cognitive reconstruction. The brain engages in a remarkable reshuffling process in an attempt to extract what is general and what is particular about each passing moment.
See the entire definition of Memory

Mongolism: Obsolete name for Down syndrome.
See the entire definition of Mongolism

Mosaic: An individual or tissue containing two or more types of genetically different cells. All females are mosaics because of X-chromosome inactivation (lyonization).
See the entire definition of Mosaic

Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.

Muscle: Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."

Myeloid: Referring to the nonlymphocytic groups of white blood cells, including the granulocytes, monocytes and platelets.
See the entire definition of Myeloid

Neck: The part of the body joining the head to the shoulders. Also, any narrow or constricted part of a bone or organ that joins its parts as, for example, the neck of the femur bone.

Nose: The external midline projection from the face.
See the entire definition of Nose

Nuchal: Referring to the back of the neck (nape). For example, nuchal rigidity is a stiff neck, sometimes a symptom of meningitis.
See the entire definition of Nuchal

Obesity: The state of being well above one's normal weight.
See the entire definition of Obesity

OCD: 1. Obsessive-compulsive disorder; 2. Osteochondritis dissecans.

Otitis: Inflammation of the ear. Depending upon which part of the ear is inflammed, there is otitis externa, otitis media, and otitis interna.

Otitis media: Inflammation of the middle ear characterized by the accumulation of fluid in the middle ear, bulging of the eardrum, pain in the ear and, if eardrum is perforated, drainage of purulent material (pus) into the ear canal.
See the entire definition of Otitis media

Ovum: An egg in the ovary of the female. This egg is called the female "gamete" or sex cell. It combines with the male gamete, called a sperm, to form a zygote. This formation process is called "fertilization." (see sperm, zygote).

Palmar: Pertaining to the palm (the grasping side) of the hand. The ancient Romans used the word "palma" for the outstretched palm of the hand.
See the entire definition of Palmar

Patent ductus: Failure of the ductus arteriosus, which functions in fetal life as an arterial shunt, to close on schedule at or shortly after birth. When the shunt remains open, it is said to be patent. See: Patent ductus arteriosus.

Patent ductus arteriosus: Failure for the ductus arteriosus, an arterial shunt in fetal life, to close on schedule.
See the entire definition of Patent ductus arteriosus

Percutaneous: Through the skin, as in a percutaneous biopsy.

Physical therapy: A branch of rehabilitative health that uses specially designed exercises and equipment to help patients regain or improve their physical abilities. Physical therapists work with many types of patients, from infants born with musculoskeletal birth defects, to adults suffering from sciatica or the after- effects of injury, to elderly post-stroke patients.

Pregnancy: The state of carrying a developing embryo or fetus within the female body. This condition can be indicated by positive results on an over-the-counter urine test, and confirmed through a blood test, ultrasound, detection of fetal heartbeat, or an X-ray. Pregnancy lasts for about nine months, measured from the date of the woman's last menstrual period (LMP). It is conventionally divided into three trimesters, each roughly three months long.
See the entire definition of Pregnancy

Prenatal: Occurring or existing before birth.
See the entire definition of Prenatal

Prenatal diagnosis: Diagnosis before birth. Methods for prenatal diagnosis include ultrasound of the uterus, placenta, and/or developing fetus; chorionic villus sampling (CVS) to obtain tissue for chromosome or biochemical analysis; and amniocentesis to obtain amniotic fluid for the analysis of chromosomes, enzymes, or DNA. A growing number of birth defects and diseases can be diagnosed prenatally, and in some cases treated before birth. Also known as antenatal diagnosis.

Psychiatric: Pertaining to or within the purview of psychiatry, the medical specialty concerned with the prevention, diagnosis, and treatment of mental illness.
See the entire definition of Psychiatric

Recurrence: The return of a sign, symptom or disease after a remission. The reappearance of cancer cells at the same site or in another location is, unfortunately, a familiar form of recurrence.
See the entire definition of Recurrence

Recurrence risk: In medical genetics, the recurrence risk is the chance that a genetic (inherited) disease present in the family will recur in that family and affect another person (or persons). It is the chance of "lightning striking twice" (or thrice, etc.).

Risk factor: Something that increases a person's chances of developing a disease.

Robertsonian translocation: A common and significant type of chromosome rearrangement that is formed by fusion of the whole long arms of two acrocentric chromosomes (chromosomes with the centromere near the very end). One in about 900 babies is born with a Robertsonian translocation making it the most common kind of chromosome rearrangement known in people. All five of the acrocentric chromosomes in people -- chromosome numbers 13, 14, 15, 21 and 22 -- have been found to engage in Robertsonian translocations. However, the formation of Robertsonian translocations was discovered by Hecht and coworkers to be highly nonrandom. Far and away the most frequent forms of Robertsonian translocations are between chromosomes 13 and 14, between 13 and 21, and between 21 and 22.
See the entire definition of Robertsonian translocation

Sleep: The body's rest cycle.
See the entire definition of Sleep

Sleep apnea: The temporary stoppage of breathing during sleep, often resulting in daytime sleepiness. Apnea is a Greek word that means "want of breath."
See the entire definition of Sleep apnea

Speech therapy: The treatment of speech and communication disorders. The approach used depends on the disorder. It may include physical exercises to strengthen the muscles used in speech (oral-motor work), speech drills to improve clarity, or sound production practice to improve articulation.
See the entire definition of Speech therapy

Sperm: A sperm is the male "gamete" or sex cell. It combines with the female "gamete," called an ovum, to form a zygote. The formation process is called "fertilization." (see ovum, zygote).

Stenosis: A narrowing, as in:

• aortic stenosis (narrowing of the aortic valve of the heart),
• pulmonary stenosis (narrowing of the pulmonary valve of the heart),
• pyloric stenosis (narrowing of the outlet of the stomach), and
• spinal stenosis (narrowing of the vertebral canal).

Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office.
See the entire definition of Surgery

Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease.
See the entire definition of Syndrome

Testicular cancer: Cancer of the male sex organ, the testicle, that normally produces the hormone testosterone. One of the most common cancers in young men. Most testicular cancers are found by men in themselves as a lump in the testicle.
See the entire definition of Testicular cancer

Tetralogy of Fallot: A combination of four heart defects that are present together at birth, accounting for about 10% of all congenital heart disease.
See the entire definition of Tetralogy of Fallot

Therapy: The treatment of disease.
See the entire definition of Therapy

Tongue: The tongue is a strong muscle anchored to the floor of the mouth. It is covered by the lingual membrane which has special areas to detect tastes.
See the entire definition of Tongue

Trisomy: The presence of three copies of a chromosome rather than the normal two. The most common trisomies in newborns are trisomy 13 (Patau syndrome), trisomy 18 syndrome (Edwards syndrome) and trisomy 21 (Down syndrome). The most common trisomy among spontaneous abortions is trisomy 16.
See the entire definition of Trisomy

Ultrasound: High-frequency sound waves. Ultrasound waves can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques. Ultrasound is often used to examine a fetus during pregnancy. There is no convincing evidence for any danger from ultrasound during pregnancy.

Umbilical cord: The cord that connects the developing embryo or fetus with the placenta and through which run the umbilical arteries and vein. The matrix (the substance) of the umbilical cord is known as Wharton's jelly and is a rich source of stem cells. At birth the umbilical cord measures about 20 inches (50 cm) in length. The cord is clamped and cut after birth and its residual tip forms the umbilicus (bellybutton).

Ventricular: Pertaining to the ventricles, the lower chambers of the heart, as in ventricular fibrillation and ventricular septal defect.

Villus: 1. A tiny finger-like or hair-like projection. 2. A small vascular protrusion.
Villus is the Latin word for shaggy hair or fleece. The plural is villi.