What is 22q11 DiGeorge Syndrome

TL;DR: 22q11 DiGeorge Syndrome is a genetic condition caused by the deletion of a small segment of chromosome 22, which disrupts the development of several body systems during fetal growth. It is characterized by a wide range of potential health challenges, including heart defects, immune system deficiencies, and learning differences, requiring a multidisciplinary care approach.

What exactly is 22q11 DiGeorge Syndrome?

22q11 DiGeorge Syndrome (also known as 22q11.2 deletion syndrome or Velocardiofacial syndrome) occurs when a small piece of chromosome 22 is missing. Because this tiny segment contains approximately 30 to 40 genes, its absence can affect the development of various body systems. While the clinical presentation of 22q11 DiGeorge Syndrome varies significantly even among family members, it typically involves the pharyngeal pouches during embryonic development, which form the thymus, parathyroid glands, and parts of the heart and facial structure.

Which body systems are affected by 22q11 DiGeorge Syndrome?

Because the genetic deletion is systemic, the impact of 22q11 DiGeorge Syndrome is multisystemic. Common manifestations include:

• Cardiac: Approximately 75% of individuals are born with congenital heart defects, most commonly involving the outflow tracts (e.g., Tetralogy of Fallot or interrupted aortic arch).


• Immunological: An underdeveloped thymus gland often leads to T-cell deficiencies, resulting in an increased susceptibility to infections.


• Endocrine: Hypocalcemia (low calcium levels) due to underdeveloped parathyroid glands is common, especially in infancy.


• Craniofacial: Features may include a cleft palate, velopharyngeal insufficiency (causing nasal speech), and distinct facial characteristics such as hooded eyelids or low-set ears.


• Neurodevelopmental: Many individuals experience developmental delays, learning disabilities, and an increased risk for psychiatric conditions like anxiety or schizophrenia later in life.

How common is 22q11 DiGeorge Syndrome?

22q11 DiGeorge Syndrome is surprisingly common for a rare disease, with an estimated prevalence of 1 in 3,000 to 1 in 6,000 live births. However, because symptoms range from mild to severe, many cases may go undiagnosed until adulthood. It affects all genders and ethnic groups equally across the globe. At DiseaseMaps.org, our community currently includes 215 members who are navigating life with 22q11 DiGeorge Syndrome, providing a vital network for shared experiences.

Is 22q11 DiGeorge Syndrome hereditary?

In the vast majority of cases (about 90%), the deletion occurs as a "de novo" mutation, meaning it happens spontaneously in the egg or sperm and is not inherited from either parent. In about 10% of cases, the condition is passed down from a parent who may have a very mild, undiagnosed form of the syndrome. A clinical geneticist can perform a microarray analysis to confirm the diagnosis and assess recurrence risks for family members.

What differentiates this from other conditions?

What makes 22q11 DiGeorge Syndrome unique is its extreme "phenotypic variability." Two people with the exact same genetic deletion can have vastly different health outcomes; one may have severe heart defects, while another may only have mild learning differences. This complexity is why early, coordinated care by a team of specialists—including cardiologists, immunologists, and speech therapists—is the gold standard for managing the condition.

Next steps

• Consult a clinical geneticist to confirm the diagnosis through chromosomal microarray testing.


• Schedule comprehensive evaluations with a pediatric cardiologist and an immunologist to establish a baseline for heart and immune health.


• Connect with the 215 members of the 22q11 DiGeorge Syndrome community on DiseaseMaps.org to share resources and find emotional support.


• Seek early intervention services for developmental or speech delays to optimize long-term learning outcomes.

Medical disclaimer: This information is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment from a qualified healthcare provider.

References

• Orphanet: 22q11.2 deletion syndrome (ORPHA:567)


• NIH GARD: 22q11.2 deletion syndrome (Genetic and Rare Diseases Information Center)


• OMIM: DiGeorge Syndrome (MIM #188400)


• The International 22q11.2 Society: Clinical practice guidelines and patient resources.