All are common in Down syndrome, except –
**Down Syndrome Associations**
**Core Concept**
Down syndrome is a genetic disorder caused by an extra copy of chromosome 21 (trisomy 21). Individuals with Down syndrome are at increased risk for various medical and developmental complications.
**Why the Correct Answer is Right**
The correct answer is related to a condition that is not commonly associated with Down syndrome. Down syndrome is characterized by intellectual disability, delayed speech, and characteristic facial features. Individuals with Down syndrome are also at increased risk for medical complications such as:
* Congenital heart defects (e.g., atrioventricular septal defect)
* Gastroesophageal reflux disease (GERD)
* Obstructive sleep apnea
* Immunodeficiency (e.g., increased susceptibility to infections)
* Alzheimer's disease (at a younger age)
**Why Each Wrong Option is Incorrect**
* **Option A:** Congenital heart defects are common in Down syndrome, with atrioventricular septal defects being one of the most common types. Therefore, this option is incorrect.
* **Option B:** Gastroesophageal reflux disease (GERD) is also a common condition in individuals with Down syndrome, likely due to anatomical and physiological factors.
* **Option C:** Obstructive sleep apnea is another common condition in Down syndrome, often due to anatomical abnormalities such as a small nasal passage or enlarged tongue.
**Clinical Pearl / High-Yield Fact**
When evaluating a patient with Down syndrome, it's essential to be aware of the increased risk for congenital heart defects and to perform a thorough cardiac evaluation as part of the initial assessment.
**Correct Answer:** D.