A genetic test looks at a person’s DNA, which is the instruction manual for our bodies. It helps determine how we grow and develop. Genes are the specific genetic instructions, inherited from our parents. Humans have about 25,000 genes.
TYPES OF GENETIC VARIANTS
Different changes, or variants, in genes can determine whether someone has a genetic condition.
|Single Nucleotide Variants (SNVs)||SNVs are smaller, single letter (nucleotide) changes in genes. These types of variants are often identified by whole exome sequencing or panel testing|
|Copy Number Variants (CNVs)||CNV is the umbrella term for a deletion (missing) or duplication (extra) piece of genetic material. This type of variant is often detected by chromosomal microarray.|
|Depending on which tests are ordered for your child, the testing may be checking for SNVs, CNVs, or both.|
With most genetic tests, there are three possible outcomes: normal or negative, abnormal or positive, and uncertain. Any one genetic test may look for only one kind of genetic change or may look for changes in only certain genes. There is not one genetic test that checks for everything, so your child may have multiple tests performed now or over time as they develop.
Normal/Negative: Getting a negative test result means that testing did not find a genetic variant that explains your child’s symptoms. Negative test results can be used to rule out one or more genetic causes of your child’s condition.
If a genetic condition is still suspected after a normal result, your provider may order follow-up testing or suggest an evaluation by a medical geneticist (a doctor specializing in genetics).
Abnormal/Positive: Getting a positive test result means that testing found a genetic variant that is known to cause developmental or health problems. This is also called a pathogenic variant.
This change is the underlying cause, or at least part of the cause, of your child’s symptoms. This information may help direct management and treatment options. These test results may also help parents determine if other family members may benefit from testing.
Variant of Uncertain Significance (VUS): Finding a VUS means that testing found a genetic variant, but it is not known for certain whether the variant is related to the symptoms in your child.
All people are expected to have some genetic variation—this is what makes us unique. These variants may or may not cause problems with the function of our genes. More research is needed to figure out which genetic variants interfere with a gene’s function (causing a genetic condition) and which variants don’t. A VUS result means that it hasn’t been figured out yet.
If you have any questions about your child’s results after testing, one of our genetic counselors can discuss them with you in detail.