Diagnosis & Testing
When Does Testing Happen?
Genetic testing for 16p11.2 can happen at many points across life. Testing is commonly ordered by a pediatrician, developmental pediatrician, neurologist, or geneticist, depending on the concern that prompts referral.
Families may be referred for testing because of:
- Delays in speech, learning, or motor skills
- Differences in behavior, attention, or social communication
- Growth, feeding, or weight concerns
- Seizures or other neurological findings
- A known family history of a genetic variance
- Breath holding syndrome or other neurologic disorders
Testing may occur in infancy, childhood, or adulthood. The sooner a diagnosis is made, the sooner proper therapies can be started, and the better the outcome will be for the patient.
Common Types of Genetic Tests
Genetic testing helps doctors find changes in DNA that may affect development. For neurodevelopmental conditions like 16p11.2, doctors most often use a chromosomal microarray (CMA), which can find missing or extra pieces of DNA called deletions or duplications. If CMA does not give an answer, other tests may be used, such as gene panel testing, whole exome sequencing (WES), or whole genome sequencing (WGS), which looks at nearly all of a person’s DNA. The test chosen depends on a person’s symptoms and what doctors are trying to understand.
Types of Genetic Testing
There are several types of genetic tests used in humans. Each looks at DNA in a different way and is used for different reasons.
- Chromosomal Microarray (CMA)
This test looks for missing or extra pieces of DNA, called deletions or duplications. It is commonly used to identify conditions like 16p11.2 and other copy number variations. - Karyotype
This test looks at chromosomes under a microscope to find large changes, such as extra or missing chromosomes. It is less detailed than newer tests. - Single‑Gene Testing
This test checks one specific gene when doctors suspect a particular genetic condition. - Gene Panel Testing
This test looks at a group of genes at the same time. It is often used when several genes could explain a person’s symptoms. - Whole Exome Sequencing (WES)
This test studies the parts of genes that give instructions to make proteins. It can help find genetic changes when other tests do not give answers. - Whole Genome Sequencing (WGS)
This test looks at nearly all of a person’s DNA, including genes and areas between them. It provides the most information but is not always needed.
Not every test finds the same types of genetic changes. Doctors choose a test based on a person’s symptoms, medical history, and what questions need to be answered.
Access to Free Genetic Testing
Some families may qualify for free clinical‑grade genetic testing through nonprofit and research‑supported programs. One option is Probably Genetic, which offers no‑cost genetic testing and genetic counseling for eligible individuals with complex or unexplained symptoms.
- Testing is physician‑ordered through their program
- Sample collection is done at home
- Genetic counseling is included Learn more at: https://www.probablygenetic.com
Where Genetic Testing is Done
Genetic testing is commonly performed through:
- Hospital‑based genetics clinics
- Major clinical laboratories (such as Invitae, Ambry, Baylor Genetics, Quest Diagnostics)
- Research or nonprofit‑supported testing programs
A doctor’s order is usually required for clinical testing.
Understanding a Test Result
A genetic report often looks complex at first, but each part has a purpose.
Results usually describe:
- The chromosome involved (for example, chromosome 16)
- The exact location on the chromosome (for example, 16p11.2)
- The type of change (deletion, duplication, or triplication)
- Whether the change is de novo or inherited
The report explains where the DNA change is, not what will happen.
What “Positive,” “Negative,” and “Uncertain” Mean
- Positive: A genetic change was found that helps explain a difference in development or health
- Negative: No relevant copy number change was found
- Variant of Uncertain Significance (VUS): A change was found, but its meaning is still being studied
Over time, uncertain findings may become clearer as research advances.
After a Diagnosis
A diagnosis is not the end of the journey. For many families, it is a starting point.
After results are shared, next steps may include:
- Meeting with a geneticist and a genetic counselor experienced in 16p11.2 genetic variances.
- Creating your medical team with referrals to specialists or therapists
- Further work up with imaging and testing if appropriate
- Educational planning or early intervention
- Connecting with other families and organizations
- Learn about the condition to the best of your ability
Not every child will need the same services. Care is personalized, and you are your child’s expert and advocate.
Talking with an Experienced Geneticist or Genetic Counselor
Genetic counselors help families:
- Understand the genetic report
- Talk through emotions and questions
- Discuss testing for other family members if needed
- Plan follow‑up care
They are trained to explain complex information clearly and compassionately and help you anticipate what your child’s care and journey will look like.