Should I screen my baby for 22q11.2 microdeletion syndrome (DiGeorge syndrome)?

Parents-to-be typically have one great hope: to have a healthy baby. There is a good chance that your hope will be realized, because most babies in the U.S. are born healthy.¹ Still, you should be aware that each year a small number of babies are born with serious genetic conditions.

What is a microdeletion?

Most people get 23 chromosomes from each biological parent. These chromosomes are arranged into pairs, totaling 46 chromosomes. Occasionally, a baby has small pieces missing from a chromosome, called a microdeletion. Microdeletions usually occur at random; they are  rarely inherited or related to any identifiable cause.²

Microdeletion syndromes involve small pieces missing from several genes. Standard prenatal genetic screens don’t always include them, and even a detailed view of the chromosomes sometimes misses them.³ To date, more than 200 microdeletion syndromes have been identified. Microdeletions can cause a range of health problems, from severe developmental or physical disorders, to very mild symptoms a person might never notice.

 22q11.2 microdeletion syndrome (DiGeorge syndrome)

The most common microdeletion syndrome is 22q11.2 deletion syndrome (or 22q for short), also referred to as DiGeorge syndrome or velocardiofacial syndrome. 22q is caused by microdeletions on chromosome 22. As with other microdeletions, the small size of the microdeletion makes it challenging to detect, even with a prenatal genetic screen designed to detect it.

22q occurs in approximately one in 2,000 to one in 6,000 births and is characterized by congenital heart defects, frequent infections, cleft palate, hypocalcemia (low calcium levels), and developmental delays.⁴ Among children affected by 22q, there is great variability in the impact of the microdeletion. Some babies have multiple serious health issues while others have almost none.⁵

Even though it is hard to detect, if your baby had 22q, you would want to know. That’s because prenatal diagnosis allows for appropriate pregnancy and neonatal management, including enhanced surveillance and interventions that could improve the outcomes for your baby, like checking for problems with their heart or blood, and making sure they are feeding correctly.

For this reason, the American College of Medical Genetics and Genomics has conditionally recommended that 22q11.2 microdeletion screening be offered to all patients.⁶

Screening for 22q

If you are pregnant, you can find out whether there is a chance your baby is affected by 22q through a simple blood test. This prenatal genetic screening, called a cell-free DNA screen, analyzes small fragments of DNA from your pregnancy. This screen can be done as early as eight weeks into your pregnancy and results are typically available in about seven to 10 days.

Not all prenatal cfDNA screens are able to accurately detect 22q. So it is important to understand which screen is best-designed to do this. For example, the Prequel® Prenatal Screen has industry-leading accuracy for the 22q microdeletion.⁷

More accurate results will help your healthcare providers assess your risk, and personalize and guide your care, which might include additional diagnostic tests—like amniocentesis or chorionic villus sampling—to confirm a diagnosis.

While there is no cure for 22q, many therapies and interventions are available. As the International 22q11.2 Foundation has written, “The earlier symptoms [related to 22q] are detected, the more doctors can do to help.”⁵

References

1. Osterman MJK, Hamilton BE, Martin JA, Driscoll AK, Valenzuela CP. Births: Final Data for 2022. National Vital Statistics Reports. 2024;73(2):1-55. Available from: https://www.cdc.gov/nchs/data/nvsr/nvsr73/nvsr73-02.pdf.
2. Children’s Hospital of Philadelphia. 22q11.2 deletion and duplication syndromes. https://www.chop.edu/conditions-diseases/22q112-deletion-and-duplication-syndromes. Accessed April 17, 2025.
3. Science Direct. Microdeletion syndrome. https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/microdeletion-syndrome. Accessed April 17, 2025.
4. Devriendt K, Fryns J-P, Mortier G, Van Thienen M-N, Keymolen K. The annual incidence of DiGeorge/velocardiofacial syndrome. J Med Genet 1998; 35: 789–790.
5. International 22q11.2 Foundation. Deletion vs. duplication. https://22q.org/what-is-22q/deletion-vs-duplication/. Accessed April 17, 2025.
6. Dungan JS, Klugman S, Darilek S, et al. Noninvasive prenatal screening (NIPS) for fetal chromosome abnormalities in a general-risk population: An evidence-based clinical guideline of the American College of Medical Genetics and Genomics (ACMG). Genet Med. 2023;25(2):100336.
7. Johansen Taber K, Hammer C, Pierson S, et al. High positive predictive value 22q11.2 microdeletion screening by prenatal cell-free DNA testing that incorporates fetal fraction amplification. Prenatal Diagnosis. Published April 16, 2024. https://doi.org/10.1002/pd.6562.