Diagnosing and Treating Genetic Diseases
Previous Page Next Page


First discovered in human adenoids (an adenoid is a tissue at the back of the throat), this group of 20-sided viruses causes respiratory and other diseases. Adenoviruses contain DNA.

One form of a gene: for example, the gene for eye color has alleles for brown, blue, black, and green eyes. An allele may be dominant or recessive.

Allergic reaction(s)
An over-reaction by the body to substances that usually do not bother the average person. Reactions include sneezing, itching, runny eyes and nose, rashes, wheezing, and shock.

Amino acid(s)
Compounds that link together to make proteins. Essential amino acids are released in the intestines when food containing protein is digested -- the body cannot make them. Non-essential amino acids can be made by the body. Amino acids contain carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.

Results when the blood doesn’t have enough red blood cells, hemoglobin, or total volume. Causes include loss of blood, an iron deficiency (so that not enough blood is formed), or a bone marrow disfunction where the blood is made. Symptoms include being tired and bone pain.

The process of taking blood, cleansing it or adding certain substances, and returning the blood to the patient.

A blood vessel which carries blood rich in oxygen and nutrients from the heart to the cells in the body.

Bacterium (bacteria)
A single-celled microscopic organism. Bacteria live in dirt and water, or in plants and animals. Some bacteria aid digestion, while others can cause diseases like pneumonia, diphtheria, and tuberculosis. They can be round, rod-shaped or spiral. Vaccinations help increase immunity to some of the diseases bacteria carry while antibiotics can fight others.

A person who has one recessive gene for a recessive genetic disease. Because the person has only one recessive gene, s/he does not have the disease, but can pass the disease gene on to her/his children.

The smallest structural unit of life capable of functioning by itself, a cell has a membrane which allows some things to pass through. Inside the cell are one or more nuclei and other cellular parts. Cells contain DNA and make up our bodies.

A steroid alcohol which regulates certain cell functions and helps build cell membranes.

Strands of deoxyribonucleic acid contain all or most of the genes of an individual. The number of chromosomes is specific to an animal or plant -- humans have 46.

Made of three consecutive nucleotides, codons specify a particular amino acid in a protein or start or stop proteins from being made.

Microorganisms (like bacteria or viruses) or tissues from plants and animals which are grown outside the body in a prepared medium in a laboratory.

The breakdown of a chemical compound into a less complex compound.

Deoxyribonucleic acid (DNA)
The molecular basis for heredity, formed in a double helix and held together by hydrogen bonds between purine and pyrimidine bases. DNA is found in the cell nucleus.

A contagious disease caused by a bacteria, which inflames the heart and nervous system and causes the formation of false membranes, especially in the throat and air passeages.

DNA marker(s)
Segments of DNA known to be linked with inheritable traits or diseases. They may not cause the condition but always appear with the genes that do. Markers are used to find the locations of genes on chromosomes.

One of a pair of alleles that suppresses the expression of the other in heterozygous (having one dominant and one recessive allele) conditions.

Embolism (Emboli)
A blockage of a blood vessel caused by an abnormal particle -- like an air bubble -- circulating in the blood.

A complex protein made by a cell which is a catalyst (something that starts a reaction or chain of events) for a specific biochemical reaction which does not change the enzyme. Enzymes control digestion, muscle contraction, and many other functions of metabolism.

When the trait a gene codes for shows in an organism’s phenotype, or body, in a detectable manner.

When a disease occurs in more people in a family than could be expected by chance alone, the disease is familial or inherited in that family.

Relating to or coming from an unborn animal, especially an animal in the later stages of pre-natal development.

A specific sequence of nucleotides in DNA or RNA, it is the unit of inheritance. A gene codes for the expression of a trait by specifying the structure of a certain protein. Usually found on a specific place on a chromosome, genes reproduce exactly during cell division, and usually occur in pairs, except for those genes on the sex chromosomes X and Y.

All the genetic information that makes an organism.

A protein in red blood cells that contains iron and transports oxygen from the lungs to the rest of the body.

When a gene has one dominant and one recessive allele.

When a gene’s alleles are either both dominate or recessive.

Human growth hormone
A protein hormone produced by the pituitary gland that promotes growth, fat mobilization, and inhibition of glucose utilization.

A cellular response to injury or stimulation from physical, chemical or biological agents. When cells inflame, they turn red, heat up, are painful, and swell to get rid of noxious agents and damaged tissue.

To receive a gene from a parent during reproduction; in humans, fetuses inherit half of their genes from their fathers and half from their mothers.

A protein hormone made by the pancreas which is necessary for metabolizing carbohydrates and sugars and which is used in the treatment and control of diabetes.

A fatty droplet of spherical lipid in suspension in tissue.

A cell made by stem cells (cells in the bone marrow which make many other kinds of cells) that goes to the lymphoid tissue in the thymus or bone marrow. They fight infections and make up a large portion of cells in the blood.

A contagious viral disease marked by a fever and rash on the neck and face. Once you’ve had measles, you generally are immune to it.

A skin tumor containing dark pigment which may be benign or malignant; when malignant (or cancerous) it spreads rapidly and widely.

A fine-pointed tube used for measuring or dispensing very small amounts -- the fluid is drawn by suction and kept in by closing the top end of the tube.

The smallest unit that something can be divided into without changing its properties. The speed of molecular motion and space between them determine if something’s a liquid, solid, or gas. Molecules are made of atoms and differ from each other in size, weight, and structure. Chemical action affects molecules.

A slippery wet substance secreted to moisten and protect tissues -- the most commonly known is nasal mucus.

A contagious viral disease with fever and swelling of the parotid gland and the salivary glands.

Having to do with the structure or function of the nervous system, which includes the brain, spinal cord, nerves, ganglion; and/or having to do with the receptors or organs that receive and interpret stimulations and send impulses to the brain and affector organs.

A basic structural unit of RNA and DNA, made of a ribose or deoxyribose sugar and a purine or pyrinidine base and a phosphate group.

Nucleus (nuclei)
The part of the cell which is enclosed in its own membrane within the cell and which contains the materials to make the chromosomes -- important in reproduction and protein making.

A living being or individual.

A complex substance made of amino acids and which include many compounds necessary for life like hormones, enzymes, and immunoglobins. Proteins are found in cells and tissue. The type of protein depends on the kinds and number of amino acids that make it. Proteins are used in building cells, cell functions, muscle contraction, digestion, growth, etc.

A cell or group of cells that responds to various stimuli, or a molecule on the surface of a cell or in the cell that responds to a certain chemical, molecule, or virus, and then makes the cell do something in reaction such as produce something, stop making something, let the stimulating material enter the cell, etc.

An allele which has little or no effect on the phenotype of an organism when paired with a more dominant allele; it only has an effect when paired with another recessive allele.

Recombinant DNA
Made by cutting up the DNA of one species (usually a bacterium) and inserting the genes of another species so that the bacterium produces the protein or hormone of the other organism.

A virus which contains RNA and which uses its RNA as a template to produce its own DNA when incorporated into the genes of infected cells.

A blockage of a blood vessel due to a blood clot.

Tissue culture(s)
Keeping alive and growing body tissue in the laboratory, outside the organism in a sterile culture medium.

An inherited characteristic which is found in the phenotype (the physical appearance) or genotype (the genetic material) of an organism. Traits include eye color, hair color, the shape of body parts and genetic diseases.

A mass of tissue with no physiological function that arises from tissue for no obvious cause; it may be benign or malignant (cancerous).

Tumor-infiltrating lymphocyte(s)
A cell isolated from a malignant tumor, cultured with interleukin-2, and injected back into the patient as a tumor-killing cell that has greater toxicity.

A blood vessel that returns blood from the body to the heart to pick up more oxygen.

A disease-causing agent that is able to live and reproduce only inside living cells. Viruses cause many infectious diseases.

White blood cell(s)
A colorless blood cell (because it doesn’t have hemoglobin) that fights invaders to the body and includes lymphocytes, monocytes, neutrophils, eosinophils, and basophils.

Whooping cough
An infectious disease caused by a bacteria that spawns a convulsive cough sometimes followed by a crowing breath. Also called "pertussis."

One of two kinds of chromosomes which help determine the sex of an organism -- females have two X-chromosomes, males have one (a Y-chromosome is the other chromosome which helps determine sex).

A genetic condition arising when an allele coding for a specific genetic trait or disease is only found on the X-chromosome. If such an allele is recessive, a female (who has two X- chromosomes) doesn’t get the trait, but a male (who has only one X- chromosome) does. X-linked traits are carried by mothers and passed to their sons.

One of two kinds of chromosomes which help determine the sex of an organism -- males have one Y-chromosome, females have none (an X-chromosome is the other chromosome which helps determine sex).

Previous Page Next Page


Revolution in Progress: Human Genetics and Medical Research/
National Institutes of Health