**Core Concept**
Acrodermatitis enteropathica is a rare genetic disorder characterized by impaired zinc absorption, leading to severe zinc deficiency. It is caused by mutations in the SLC39A4 gene, which encodes a zinc transporter responsible for zinc uptake in the small intestine.

**Why the Correct Answer is Right**
The correct answer is B. AR, indicating that acrodermatitis enteropathica is inherited in an autosomal recessive (AR) pattern. This means that an individual must inherit two copies of the mutated SLC39A4 gene, one from each parent, to express the disease. The disease is usually seen in infants and young children, who are unable to absorb sufficient zinc from their diet due to the genetic defect. The impaired zinc absorption leads to a range of symptoms, including skin lesions, hair loss, and impaired growth and development.

**Why Each Wrong Option is Incorrect**
**Option A:** Acrodermatitis enteropathica is not inherited in an autosomal dominant (AD) pattern, as each parent would only need to contribute one copy of the mutated gene for the disease to be expressed.

**Option C:** While X-linked recessive disorders are caused by mutations in genes on the X chromosome, acrodermatitis enteropathica is caused by mutations in the SLC39A4 gene on chromosome 8, making it an autosomal disorder.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that acrodermatitis enteropathica is a rare but important diagnosis to consider in infants and young children with severe zinc deficiency, as prompt treatment with zinc supplements can improve symptoms and prevent long-term complications.

**✓ Correct Answer: B. AR. Autosomal recessive inheritance pattern.**