Third Street Eyecare

500 South Third Street, Suite 105, Geneva, IL 60134

(630) 232-7800

Geneva Optometrist

Geneva Eye Doctor

Genetics Definitions


The Particular form of a gene, sequence or a base.


One of 4 molecules that hold the 2 strands of DNA in a chromosome together, The sequence of the bases in a gene determine the structure of proteins.

Birth Defect

An abnormal condition that occurs before or at birth. Birth defects can cause physical and developmental problems that may require special medical care or therapy.

Carrier Status

The knowledge of whether a healthy person has a disease-causing gene change that could be passed down to his or her children. Carrier status is often determined by genetic screening.


A smallmembrane-bound compartment, filled with chemicals; the subunit of all living things, including humans.

Chorionic Vilus Cells

Cells contained in the tissue of the placenta in early pregnancy. The tissue contains the same genetic information as the developing fetus.


A package of DNA. The largest package is chromosome 1, the smallest is chromosome 22.

Diagnostic Testing

A test to confirm the presence or absence of a specific disease or condition.


The two allelic forms of a gene, sequence or base found on the maternal and paternal DNA strands.

DNA (Deoxyribonucleic Acid)

A large molecule that carries all of the genetic information needed to operate a cell, make tissues and control organ systems.

DNA Banking

The process of preserving and saving a person's DNA sample for future testing.


A protein that speeds up a biochemical reaction. Enzymes are critical to cell functions.


A subunit of DNA that contains the message for a cell product, typically some type of protein such as an enzyme. Humans have approximately 25,000 genes.


A trait or condition determined by one or more genes.


The complete set of DNA found in all 23 chromosomes. Each species has its own genome.


The identity of a base at a single site


The collection of DNA variation found on the same strand of DNA (i.e, on one chromosome). A haplotype may be restricted to a short sequene or to an entire chromosome.

Linkage Disequilibrium

The tendency of DNA segments to be inherited with others that are located close by. The farther apart DNA segments on the same chromosomal strand are from one another, the greater the likelihood that they will become separated from one another during cell division. Two DNA markers that are always inherited together are said to be in "absolute linkage disequilibrium".


A chemical combination of two or more atoms that form a specific chemical substance; the smallest unit of a substance that displays characteristic physical and chemical properties.


An induced alteration in the ancestral DNA sequence.


The chemical description of the bases that make up DNA.

Predictive Testing

A genetic test to determine if a person has one or more gene changes that increase the risk of developing a certain disease or condition at some time in the future.

Pre-Symptomatic Testing

A genetic test performed before the on set of any symptoms to determine if a person has a gene change that will eventually cause a certain disease or condition.


A large complex molecule essential to body structure, function and regulation. Examples include hormones, enzymes, and antibodies. Proteins are determined by the DNA sequences within genes.


A DNA base chemical group that contains the double ringed guanine and adenine.


A DNA base chemical group that contains the single ringed thymine and adenine.

RNA (Ribonucleic Acid)

A cell molecule similar to DNA. It plays an important role in making proteins and other cell activities.


The process of looking for a particular gene change or disease in individuals who don't exhibit any signs or symptoms.


A Single Nucleotide Polymorphism is a specific site of naturally occuring variation in the human genome that has been inherited over many generations. By convention, if the variation is found in more than 1% of the time it is called a "SNP," if it is found less frequently it is called a "mutation."

Office Hours

Monday: 10:00am - 5:00pm
Tuesday: 10:00am - 6:00pm
Wednesday: 10:00am - 5:00pm
Thursday: 10:00am - 7:00pm
Friday: 10:00am - 5:00pm
Saturday: 10:00am - 2:00pm
Sunday: Closed

Office Info

500 South Third Street, Suite 105
Geneva, IL 60134
Phone: (630) 232-7800

We are conveniently located off of the Geneva Metra West line, 1/2 of a block away.