Anomaly associated with duodenal atresia is
**Core Concept**
Duodenal atresia is a congenital anomaly characterized by the complete or partial closure of the duodenum, leading to intestinal obstruction. This condition is often associated with other congenital anomalies due to the early developmental origin of the duodenum.
**Why the Correct Answer is Right**
The most common anomaly associated with duodenal atresia is Down syndrome. This is because the development of the duodenum and the formation of the duodenal atresia are influenced by genetic factors. In particular, the 21st chromosome, which is involved in the development of Down syndrome, plays a crucial role in the formation of the duodenum. The increased risk of duodenal atresia in Down syndrome patients is thought to be due to the disruption of the normal genetic pathways that regulate duodenal development.
**Why Each Wrong Option is Incorrect**
* **Option A:** Trisomy 18 is another chromosomal disorder associated with congenital anomalies, but it is not the most common anomaly associated with duodenal atresia.
* **Option B:** Trisomy 13 is a chromosomal disorder that involves severe congenital anomalies, but it is not specifically associated with duodenal atresia.
* **Option C:** Intestinal malrotation is a condition where the intestine does not form properly, but it is not the most common anomaly associated with duodenal atresia.
**Clinical Pearl / High-Yield Fact**
Duodenal atresia is often diagnosed prenatally using ultrasound, and it is essential to investigate for associated anomalies, particularly Down syndrome, in affected patients.
**Correct Answer: A. Down syndrome**