**Question:** Selective protein loss is seen in -

A. Acrodermatitis Enteropathica
B. Wilson's disease
C. Familial Mediterranean Fever
D. Ehlers-Danlos Syndrome

**Core Concept:**
Selective protein loss is a condition characterized by the deficiency or dysfunction of specific proteins, leading to abnormal protein transport or excretion. In medical exams, selective protein loss can be categorized into two types: selective loss of zinc (ZIP) proteins or copper (ATP7B) proteins.

**Why the Correct Answer is Right:**
Selective protein loss in Acrodermatitis Enteropathica (AE) is due to a deficiency in ZIP4 (SLC39A4), a zinc transporter protein. Zinc is essential for proper functioning of various enzymes and transcription factors, and its deficiency leads to impaired intestinal absorption of zinc, causing diarrhea, growth failure, and skin inflammation.

**Why Each Wrong Option is Incorrect:**
Wilson's disease (option B) is caused by mutations in the ATP7B gene, leading to copper accumulation in tissues. In contrast, selective protein loss refers to zinc deficiency, not copper deficiency.

Familial Mediterranean Fever (FMF) is an autoimmune disorder characterized by recurrent attacks of fever and polyserositis. It is not related to selective protein loss.

Ehlers-Danlos Syndrome (option D) is a group of heritable connective tissue disorders characterized by loose joints, skin hyper-extensibility, and joint hypermobility. It is unrelated to selective protein loss.

**Clinical Pearl:**
Selective protein loss can be diagnosed through laboratory tests, such as serum zinc levels, and treatment typically involves zinc supplementation. Zinc deficiency can also lead to other symptoms like alopecia, growth retardation, and peripheral neuropathy. Zinc deficiency is a common nutritional issue in developing countries, especially in diets low in zinc-rich foods like meat, nuts, and dairy products.