A 3-month-old infant is diagnosed with a deletion at the 22q11 chromosome. A routine cardiovascular examination reveals severe congenital cardiac malformation. Which of the following malformations will most likely be associated with 22q11 syndrome?
## **Core Concept**
The 22q11.2 deletion syndrome, also known as DiGeorge syndrome or velocardiofacial syndrome, is a disorder caused by a small segment deletion on chromosome 22. This condition is characterized by various anomalies, including congenital heart problems, cleft palate, immune deficiency, and characteristic facial features. The cardiovascular malformations associated with this syndrome are diverse but often involve the outflow tracts of the heart.
## **Why the Correct Answer is Right**
The correct answer, , is associated with 22q11 syndrome because this deletion is known to cause a variety of congenital heart defects, with **interrupted aortic arch** and **truncus arteriosus** being particularly prevalent. However, the most common cardiac anomalies include **truncus arteriosus**, **tetralogy of Fallot**, and **interrupted aortic arch**. Truncus arteriosus, in particular, is highly associated with 22q11.2 deletion syndrome. This condition involves a single blood vessel coming out of the heart, instead of the usual two separate vessels, resulting from the abnormal development of the outflow tracts.
## **Why Each Wrong Option is Incorrect**
- **Option A:** While certain cardiac malformations can present with similar features, they are not as strongly associated with 22q11 syndrome as .
- **Option B:** This option might represent a different congenital heart defect, but it is not the most commonly associated with 22q11 syndrome.
- **Option C:** Similarly, this could represent another cardiac anomaly, but it lacks the specific association with 22q11 deletion syndrome that does.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl for 22q11 syndrome is that patients often present with **hypocalcemia** (due to parathyroid gland dysfunction), **cardiac defects**, and **immunodeficiency** (due to thymic hypoplasia). The association with congenital heart defects, particularly **truncus arteriosus**, is a critical consideration in the diagnosis and management of patients with 22q11 syndrome.
## **Correct Answer:** . Truncus Arteriosus