Glossary

To help you better understand the content provided on this Web site, we have provided below a list of frequently used words and their meaning. If you do not see a word that you may have a question about, please contact us directly and we will try to answer any questions you may have.

Alleles:

Genes that carry inheritable characteristics. Alleles come in pairs, and the 2 genes together determine the characteristic. Homozygous alleles refer to pairings with 2 identical genes, heterozygous alleles refer to pairings of 2 different genes.

Alpha1-antitrypsin deficiency (AAT Deficiency or AATD):

An inherited genetic condition where the body is unable to produce adequate amounts of an enzyme called alpha-1 antitrypsin (AAT). Inadequate amounts of AAT can lead to chronic conditions affecting primarily the lungs in adults and less frequently, the liver in children and adults.

Chromosomes:

One of the threadlike "packages" of genes and other DNA in the nucleus of each cell. Different kinds of organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes, 46 in all. Each parent contributes one chromosome to each pair, so children get half of their chromosomes from their mother and half from their father.

COPD (chronic obstructive pulmonary disease):

A term used for a group of conditions that affect the lungs' ability to take in and expel air. Emphysema is an example of COPD.

DNA (deoxyribonucleic acid):

The molecule that encodes genetic information.

FEV1 (Forced Expiratory Volume, 1 second):

FEV1 is how much air you can breathe out in one second. It measures the flow of air in the large airways of the lung and is a measure of how healthy your lungs are. An FEV1 test is usually performed either in your doctor's office or in a pulmonary function test lab.

Genes:

The functional and physical unit of heredity passed from parent to child. Genes are sequences of DNA. Many genes contain the information for making a specific protein, others are regulatory in function and determine when and where in the body proteins are made.

Genome:

All the genetic material (DNA) in all chromosomes of a cell of a particular organism.

Genotype:

The total hereditary information present in an individual. Also, genotype can refer to the specific genes that produce a certain characteristic, for example, eye color, or protein such as Alpha-1.

M, S and Z alleles:

There are 3 variants (alleles) of the AAT gene called M, S and Z. M is the "healthy" gene, which directs the body to produce a normal AAT protein which is secreted into the bloodstream and can neutralize the elastase. S and Z however are defective versions that direct the body to produce a nonfunctional AAT protein.

Neutrophil elastase:

An enzyme that functions as a proteinase. It is made by white blood cells that move through tissues and guard the body against invaders.

Panniculitis:

A swelling or inflammation of tissue underneath the skin. Severe Alpha-1 patients can sometimes experience multiple painful nodules underneath the skin.

Phenotype:

The physical expression of the characteristics produced by genes present in an individual. Eye color, blood type, and hair color are examples of phenotypes produced by genes. Phenotypes can also refer to the actual protein produced by a certain gene.

Proteinase Inhibitor:

An enzyme that stops or slows the activity of proteinases. Proteinases are enzymes that break down proteins. AAT is a proteinase inhibitor that stops a normally present proteinase in the lungs from attacking normal lung tissue. Without sufficient levels of AAT, lung tissue can be destroyed over time leading to decreased lung function.

Vasculitis:

Swelling or inflammation of blood vessels, also sometimes occurring in severe Alpha-1 patients.