**Question:** Which of the following is not a malabsorption syndrome:

A. Celiac Disease
B. Inflammatory Bowel Disease (Crohn's Disease/Ulcerative Colitis)
C. Cystic Fibrosis
D. Diverticular Disease

**Correct Answer: D.** Diverticular Disease

**Core Concept:** Malabsorption syndromes are a group of disorders characterized by impaired nutrient absorption in the gastrointestinal tract. These conditions can lead to malnutrition, weight loss, and other symptoms.

**Why the Correct Answer is Right:** Diverticular Disease refers to the presence of pouches (diverticula) in the wall of the large intestine (colon). While it can cause some gastrointestinal symptoms, it primarily affects the large bowel and does not primarily involve the small intestine, where nutrient absorption primarily occurs. Malabsorption syndromes should involve the small intestine.

**Why Each Wrong Option is Incorrect:**

A. Celiac Disease (Celiac Sprue): This autoimmune disorder affects the small intestine and results in malabsorption due to damage to the villi and enterocytes, leading to malabsorption of nutrients.

B. Inflammatory Bowel Disease (Crohn's Disease/Ulcerative Colitis): Both Crohn's Disease and Ulcerative Colitis primarily affect the large intestine and cause inflammation, leading to malabsorption of nutrients.

C. Cystic Fibrosis: This genetic disorder primarily affects the exocrine glands and lungs, leading to impaired sweat gland function and pancreatic insufficiency. Malabsorption is not the primary focus of Cystic Fibrosis.

**Clinical Pearl:** Malabsorption syndromes are diverse conditions that should predominantly affect the small intestine for proper diagnosis. Understanding the key organs and processes involved in nutrient absorption (villi, enterocytes, and brush border enzymes) is essential for recognizing malabsorption syndromes.