Is DiGeorge Syndrome (22q11.2 deletion) Genetic?

How Genetic Is DiGeorge Syndrome (22q11.2 deletion)?

DiGeorge Syndrome (22q11.2 deletion) has a strong genetic basis. Research estimates heritability at approximately 100%, meaning genetic factors account for the majority of variation in whether individuals develop this condition.

Key genes associated with DiGeorge Syndrome (22q11.2 deletion): TBX1. Variants in these genes have been identified through genome-wide association studies (GWAS) and clinical research as influencing susceptibility or severity.

Source: MedlinePlus Genetics

Does Family History Matter for DiGeorge Syndrome (22q11.2 deletion)?

Yes — family history is one of the strongest predictors of DiGeorge Syndrome (22q11.2 deletion). If a first-degree relative (parent, sibling, or child) has been diagnosed, your own risk may be significantly elevated. Discussing your family history with a healthcare provider or genetic counsellor is strongly recommended.

Is 22q11.2 Deletion Syndrome Inherited, or Does It Happen New?

Most cases are not inherited from a parent. Per NORD (the National Organization for Rare Disorders), the 22q11.2 microdeletion "occurs as a new abnormality in 93% of those affected and is inherited from a parent in 7% of those affected." In other words, in roughly 9 out of 10 cases, neither parent carries the deletion — it arises spontaneously (a de novo event) during the formation of an egg or sperm cell or very early in development, and the parents' own chance of having another affected child is low, though not zero, because of a small possibility of the deletion being present in only some of a parent's reproductive cells (germline mosaicism).

In the remaining roughly 7% of cases, a parent carries the same 22q11.2 deletion — sometimes with mild or no obvious symptoms themselves — and the condition follows a genuine autosomal dominant pattern: each child of that parent has approximately a 50% chance of inheriting the deletion. This is exactly why genetic testing (see below) is recommended for parents once a child is diagnosed — it directly changes the family's own recurrence-risk conversation, not just the affected child's care.

Source: NORD — Chromosome 22q11.2 Deletion Syndrome

Is Genetic Testing for DiGeorge Syndrome Worth It?

Unlike several other conditions on this site, genetic testing here is directly diagnostic, not just a risk estimate. A 22q11.2 deletion is confirmed clinically with FISH (fluorescence in situ hybridization) testing or, increasingly, chromosomal microarray analysis — both of which can detect the missing segment of chromosome 22 directly, rather than inferring risk from family history alone. Once a child is diagnosed, testing both parents is the standard next step: it distinguishes a de novo case (recurrence risk for future children is low) from an inherited one (each future child has roughly a 50% recurrence risk, and the carrier parent's own relatives may benefit from testing too).

A consumer DNA panel like CircleDNA is not a substitute for clinical FISH or microarray testing — it is not designed or validated to detect a chromosomal microdeletion of this kind. For families who already have a diagnosis, mapping out who else in the family may carry the deletion is the genuinely useful next step. Our Family History Risk Checker walks through a few questions about affected relatives and returns a plain-language read on your own inherited risk — an interactive step neither NORD's nor Mayo Clinic's 22q11.2 pages offer.

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