**Core Concept**
Beckwith-Wiedemann syndrome (BWS) is a genetic disorder characterized by an overgrowth of various tissues and organs, often associated with an increased risk of childhood tumors. It is caused by an abnormality in the imprinted region of chromosome 11p15.5, leading to overexpression of genes involved in cell growth and proliferation.

**Why the Correct Answer is Right**
Hyperglycemia is not a characteristic feature of Beckwith-Wiedemann syndrome. The syndrome is typically associated with hypoglycemia due to overproduction of insulin-like growth factor II (IGF-II), which can cause an excessive glucose uptake by cells. This leads to low blood glucose levels, especially in the first few months of life.

**Why Each Wrong Option is Incorrect**
* **Option A:** Omphalocele is indeed a feature of Beckwith-Wiedemann syndrome. Infants with BWS often have an omphalocele, which is a congenital defect where the intestines or other organs protrude through the navel.
* **Option B:** Macrosomia is a common feature of Beckwith-Wiedemann syndrome. Affected individuals often have an increased birth weight and tall stature.
* **Option D:** Visceromegaly, particularly macroglossia (enlarged tongue) and hepatomegaly (enlarged liver), are also characteristic features of BWS. The overgrowth of various organs and tissues is a hallmark of the syndrome.

**Clinical Pearl / High-Yield Fact**
Beckwith-Wiedemann syndrome is associated with an increased risk of various childhood tumors, including Wilms tumor, hepatoblastoma, and adrenocortical carcinoma. Regular surveillance and monitoring are essential for early detection and management of these malignancies.

**✓ Correct Answer: C. Hyperglycemia**