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Think of 22q11.2 deletion syndrome as one chromosomal deletion linking three exam worlds: congenital abnormalities, immune and calcium problems, and a striking later vulnerability to psychosis.

22q11.2 deletion syndrome is caused by a heterozygous deletion on chromosome 22. The recurrent deletion removes several genes and produces variable developmental effects. Palatal and conotruncal cardiac abnormalities, immune deficiency and hypocalcaemia can identify the syndrome early; schizophreniaA long-term mental illness involving episodes of psychosis such as hallucinations and delusions.Read more → becomes a major adult psychiatric association.

Look for conotruncal congenital heart disease, cleft or insufficient palate, hypocalcaemia or immune deficiency alongside later psychosis.

• 22q11.2 deletion vs fragile X syndrome, a chromosomal microdeletion with cardiac, palatal and calcium clues contrasts with an FMR1 repeat expansion.
• 22q11.2 deletion vs Down syndrome, the former is a chromosome 22 microdeletion, whereas Down syndrome is trisomy 21.
• 22q11.2 deletion vs Wilson disease, congenital multisystem clues and molecular testing differ from a copper-metabolism disorder assessed biochemically.

Trap, treating DiGeorge and velocardiofacial syndrome as unrelated diagnoses. Resolution: both sit within the 22q11.2 deletion syndrome spectrum.

Trap, remembering only childhood congenital features. Resolution: carry the association forward into adulthood, when psychotic illness becomes especially important.

Cluster the clues by life stage, congenital anatomy, immune or endocrine abnormalities, then neurodevelopmental and psychiatric outcomes. Confirm the chromosomal deletion rather than guessing from one feature.