Reference
Plain-English definitions of the genetics terms you will meet in a report, a guide or a conversation with your clinician.
Updated
A
- Activity score
- A number used for some genes, such as CYP2D6, to sum up how active an enzyme is likely to be. Each version of the gene gets a value between 0 and 1, and the two values are added together.From genotype to metabolizer status
- ACTN3
- A gene that makes alpha-actinin-3, a protein found mostly in fast-twitch muscle fibers, the ones used for speed and power. Because of a common variant, R577X, some people make none of it. Studies of athletes link it with sprint and endurance events, but the links are small and can’t say what any one person can do.What is the ACTN3 gene?
- Allele
- One version of a gene or of a stretch of DNA. You inherit one allele of most genes from each parent.
- APOE
- A gene that makes apolipoprotein E, a protein that carries cholesterol and other fats in the blood. Its common versions are called ε2, ε3 and ε4. Some of them are linked with health conditions later in life, so a result is best talked through with a clinician or genetic counselor.
B
- BRCA1
- A gene that helps repair damaged DNA. Some inherited variants stop it working properly and raise the chance of breast and ovarian cancer, and of some other cancers. If you or a close relative has had one of these cancers, ask your doctor about full-gene clinical testing.Testing for inherited cancer risk is a screening test, not a diagnosis. A result with no variant found does not mean you will not develop cancer, and finding a variant does not mean you will. Talk to your doctor or a genetic counselor before making any decision about screening, medication or surgery.GeneCancer: selected variants, by genotyping
- BRCA2
- A gene that works alongside BRCA1 in repairing DNA. Some inherited variants raise the chance of breast and ovarian cancer, and of some other cancers, including prostate and pancreatic cancer. If you or a close relative has had one of these cancers, ask your doctor about full-gene clinical testing.Testing for inherited cancer risk is a screening test, not a diagnosis. A result with no variant found does not mean you will not develop cancer, and finding a variant does not mean you will. Talk to your doctor or a genetic counselor before making any decision about screening, medication or surgery.GeneCancer: selected variants, by genotyping
C
- Carrier screening
- A test that shows whether you carry a variant that could cause a condition in a child, often only if both parents pass on a variant in the same gene. Carriers are usually healthy themselves.
- Cascade testing
- Offering testing to the blood relatives of someone found to carry an inherited variant, starting with the closest relatives, so they can learn whether they carry it too.
- CLIA
- The Clinical Laboratory Improvement Amendments: the U.S. federal rules that set quality standards for laboratories that test samples from people.Our lab
- Copy number
- How many copies of a stretch of DNA you carry. Most genes come in two copies, one from each parent, but some stretches can be missing, doubled or repeated. Reading a single DNA letter doesn’t show how many copies there are.An example: the starch gene AMY1
- CPIC
- The Clinical Pharmacogenetics Implementation Consortium. It publishes freely available, peer-reviewed guidelines on how a genetic result can be used for specific medicines.Where the guidance comes from
- CYP1A2
- The gene for the liver enzyme that does most of the work of breaking down caffeine. Variants near it are linked with how much caffeine people tend to take in, but age, hormones, smoking and diet also change how fast caffeine is cleared.Is there a caffeine gene?
- CYP2C19
- A gene for a liver enzyme that helps process a number of medicines, including some antidepressants, some stomach-acid medicines and an anti-clotting heart medicine. Your versions of it can make you a slower or faster processor of those medicines.Pharmacogenomics at GeneMatrix
- CYP2C9
- A gene for a liver enzyme that helps process some anti-inflammatory painkillers, a seizure medicine and a blood thinner. Some versions make the enzyme less active.Pharmacogenomics at GeneMatrix
- CYP2D6
- A gene for a liver enzyme that helps process many medicines, including some antidepressants and some opioid pain medicines. Some people carry extra or missing copies of the whole gene.Pharmacogenomics at GeneMatrix
- CYP3A4
- A gene for an enzyme in the liver and gut that helps process a large share of medicines. Other medicines and some foods can speed it up or slow it down.
- Cytochrome P450 (CYP)
- A family of enzymes, many of them in the liver, that break down a large share of medicines. Genes in this family, such as CYP2D6 and CYP2C19, are among those most often read in pharmacogenomics.
D
- Deletion/duplication
- A kind of variant in which a stretch of DNA, sometimes part or all of a gene, is missing (a deletion) or copied (a duplication). A test that checks selected single-letter variants may not detect it.
- Diplotype
- The pair of star alleles you carry for one gene, one on each copy, written like *1/*2.
- DPYD
- A gene for the enzyme that breaks down fluoropyrimidines, a group of chemotherapy medicines. Some variants make the enzyme less active, so the medicine can build up. Guidance exists on how prescribers can use a result.Pharmacogenomic results describe how your body is likely to process certain medicines. They do not tell you whether a medicine will work for you, and they are not dosing instructions. Never start, stop or change a medication because of a genetic result. Bring it to the prescriber who manages your medicines.Pharmacogenomics at GeneMatrix
E
- Exome
- The parts of your genes that carry the instructions for making proteins. Together they make up only a small part of your DNA.
F
- FTO
- A gene where common variants are linked with small average differences in body mass index (BMI). It is one of many places in the genome linked with body weight, each with a small effect, and people who carry its variants respond to diet and activity programs as well as people who don’t.Genes and body weight
G
- GeneCancer
- Our test for selected inherited variants linked with higher cancer risk, in genes including BRCA1 and BRCA2, checked by genotyping. Selected variants only: it isn’t a full-gene test, and a result with no variant found doesn’t rule out inherited risk. If you or a close relative has had cancer, ask your doctor about full-gene clinical testing.Testing for inherited cancer risk is a screening test, not a diagnosis. A result with no variant found does not mean you will not develop cancer, and finding a variant does not mean you will. Talk to your doctor or a genetic counselor before making any decision about screening, medication or surgery.GeneCancer: selected variants, by genotyping
- GeneCore
- Our all-in-one Nutrigenomics test. It reads diet, fitness and everyday health traits from one saliva sample and sets them side by side in one report, for general wellness and information.Our nutrition, supplement, athletic and wellbeing reports are for general wellness and information. The evidence behind these associations is less established than for our clinical panels, and these reports are not intended to diagnose, treat, cure or prevent any disease.GeneCore
- GeneMatrix+ re-read
- A new reading of the genetic results you already have, sent to you as an updated report. Re-reads come with GeneMatrix+ while it is active, and you don’t send a new sample.GeneMatrix+
- GenePGx
- Our pharmacogenomics test. It uses genotyping to check selected variants in genes that affect how your body is likely to process certain medicines, and sets the results out in one report to read with your prescriber.Pharmacogenomic results describe how your body is likely to process certain medicines. They do not tell you whether a medicine will work for you, and they are not dosing instructions. Never start, stop or change a medication because of a genetic result. Bring it to the prescriber who manages your medicines.GenePGx
- Genetic association
- A statistical link, found by studying large groups of people, between a variant and a trait: the variant turns up a little more or less often in people with the trait. It describes groups, and doesn’t mean the variant causes the trait in you.How a nutrigenomics test works
- Genome-wide association study (GWAS)
- A study that checks a very large number of variants across the whole genome in many people, looking for ones that turn up more often with a trait. Most of the links it finds have small effects.
- Genotype
- The versions of a gene you carry at the positions a test looks at.
- Genotyping
- A lab method that checks a set of known variants, chosen in advance, at specific places in your DNA. It doesn’t read whole genes, so it can’t find variants it doesn’t look for. Our genetic tests use genotyping.How our testing works
- Germline
- Inherited DNA, present in almost every cell of your body. Germline variants are the ones a genetic test from saliva reads, as opposed to changes that arise later in one tissue.
H
- Haplotype
- A set of variants inherited together on the same copy of a chromosome. Star alleles in pharmacogenomics are haplotypes: what matters is the combination of variants on each copy.
- Hereditary cancer syndrome
- A condition passed down in families in which an inherited variant in one gene raises the chance of certain cancers. Examples include hereditary breast and ovarian cancer, linked with BRCA1 and BRCA2, and Lynch syndrome.
- Heritability
- How much of the variation in a trait across a group of people is linked to genetic differences between them. It describes a population, not how much of your own trait comes from your genes.How much genes matter in sport
- HLA-B
- An immune-system gene. A few of its variants are linked with rare but serious reactions to specific medicines.
L
- Laboratory-developed test
- A test designed, validated and run within a single laboratory, rather than sold as a kit to many labs.How our testing works
- Lactase persistence
- Continuing to make lactase, the enzyme that digests the sugar in milk, into adulthood. It is controlled by a stretch of DNA near the LCT gene, and how common it is varies a lot by ancestry. A gene result for it isn’t a test for lactose intolerance.Lactose: do you keep making lactase?
- Lynch syndrome
- An inherited condition caused by a variant in one of the DNA-repair genes MLH1, MSH2, MSH6 or PMS2, or in EPCAM, a neighboring gene that can switch MSH2 off. It raises the chance of colorectal, endometrial and some other cancers.
M
- Metabolizer status
- A standard term for how active a medicine-processing enzyme is likely to be: poor, intermediate, normal, rapid or ultrarapid. “Extensive metabolizer” is an older name for normal.How metabolizer status is worked out
- MTHFR
- A gene for an enzyme your body uses to process folate. Some of its variants, such as C677T, are very common. The CDC says people who carry them can process all forms of folate, including folic acid, and medical geneticists have found little clinical use in testing for them.MTHFR test: what it can and can’t tell you
N
- NCCN Guidelines
- Guidelines from the National Comprehensive Cancer Network, an alliance of U.S. cancer centers. Among other things, they set out who may be offered inherited cancer testing and what care may follow a result.
- Nutrigenomics
- The study of how genetic variation relates to diet, nutrients and related traits.Our nutrition, supplement, athletic and wellbeing reports are for general wellness and information. The evidence behind these associations is less established than for our clinical panels, and these reports are not intended to diagnose, treat, cure or prevent any disease.Nutrigenomics at GeneMatrix
O
- Oral microbiome
- The community of bacteria and other microbes that live in your mouth. Oral Health DNA measures the DNA of microbes in your saliva, not your own DNA.Oral Health DNA is a laboratory-developed test performed in our own CLIA-certified laboratory. New York is the exception: orders shipped there are completed through a physician order or a reference laboratory permitted in New York. It has not been cleared or approved by the FDA. It measures the DNA of microbes in your saliva, not your DNA: it is not a genetic test, not a diagnosis, and not a prediction of any disease.Oral Health DNA
P
- Penetrance
- How often people who carry a particular variant go on to show the related trait or condition. A variant with incomplete penetrance doesn’t show in everyone who carries it.
- Pharmacogenomics (PGx)
- The study of how the genes you inherited affect the way your body handles medicines.Pharmacogenomic results describe how your body is likely to process certain medicines. They do not tell you whether a medicine will work for you, and they are not dosing instructions. Never start, stop or change a medication because of a genetic result. Bring it to the prescriber who manages your medicines.How pharmacogenomics works
- Phenotype
- A trait that results from your genes and other factors. In pharmacogenomics, it usually means your metabolizer status.
- Polygenic risk score (PRS)
- A score that adds up the small effects of many common variants into one estimate for a trait or condition. It describes a tendency, not a diagnosis, and it can work less well for people whose ancestry is under-represented in the research behind it.
S
- Selected variants
- The specific, known variants a genotyping test is designed to check. A test of selected variants can’t find variants it doesn’t look for, so a result with none found doesn’t rule out others.
- SLCO1B1
- A gene for a transporter that carries some statins, a group of cholesterol medicines, into the liver. With some variants, less of the medicine reaches the liver and more stays in the blood.Pharmacogenomic results describe how your body is likely to process certain medicines. They do not tell you whether a medicine will work for you, and they are not dosing instructions. Never start, stop or change a medication because of a genetic result. Bring it to the prescriber who manages your medicines.Pharmacogenomics at GeneMatrix
- SNP (single-nucleotide polymorphism)
- A difference of a single DNA letter at one spot, common enough to be shared by many people. It is the most common kind of variant, and the kind genotyping usually reads.
- Somatic
- Describes a DNA change that arises during life in some of your cells, such as in a tumor, rather than being inherited. A saliva test of inherited DNA isn’t designed to find somatic changes.
- Star allele
- A standard name, such as *1 or *2, for a known version of a medicine-processing gene.
T
- TPMT
- A gene for an enzyme that breaks down thiopurines, a group of medicines that dampen the immune system. People with less active versions can build up more of the medicine. Guidance exists on how prescribers can use a result.Pharmacogenomic results describe how your body is likely to process certain medicines. They do not tell you whether a medicine will work for you, and they are not dosing instructions. Never start, stop or change a medication because of a genetic result. Bring it to the prescriber who manages your medicines.Pharmacogenomics at GeneMatrix
- Transporter
- A protein that moves a medicine into or out of cells, for example into the liver. Variants in transporter genes can change how much of a medicine stays in the body.
V
- Variant
- A place where your DNA differs from a common reference. Most variants are harmless; a few change how a gene works.
- Variant of uncertain significance (VUS)
- A variant whose effect on health isn’t known yet. It isn’t a positive result, and it shouldn’t be the basis of a medical decision on its own. As evidence builds, it may be reclassified.
- VKORC1
- The gene for the enzyme that the blood thinner warfarin acts on. Some variants make people more sensitive to it. Guidance exists on how prescribers can use a result, alongside CYP2C9.Pharmacogenomic results describe how your body is likely to process certain medicines. They do not tell you whether a medicine will work for you, and they are not dosing instructions. Never start, stop or change a medication because of a genetic result. Bring it to the prescriber who manages your medicines.Pharmacogenomics at GeneMatrix
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