Which condition is associated with the ultrasound finding of duodenal atresia?

Duodenal atresia is primarily associated with Down syndrome, also known as Trisomy 21 (T21), which helps clarify why the correct choice is the first one related to this condition. In prenatal ultrasounds, duodenal atresia can be detected by the presence of the "double bubble" sign, indicating distention of both the stomach and proximal duodenum, with no further passage of fluid or air beyond this area.

While Turner syndrome, cystic fibrosis, maternal diabetes, and thanatophoric dysplasia have various associations with gastrointestinal anomalies, they do not typically present with the hallmark ultrasound finding of duodenal atresia. Down syndrome, in particular, shows a higher incidence of congenital heart defects as well as gastrointestinal anomalies like duodenal atresia, making it a key condition to consider in the differential diagnosis when such findings are noted on an ultrasound. Understanding these associations is crucial for genetic counselors and healthcare professionals when interpreting ultrasound findings and guiding families accordingly.