In congenital dystrophic variety of epidermolysis bullosa, mutation is seen in the gene conding for –
**Core Concept**
Epidermolysis bullosa (EB) is a group of genetic disorders characterized by skin fragility and blistering due to mutations in genes encoding for proteins crucial for skin integrity. The congenital dystrophic variety of EB is a severe form of the disease, often resulting in extensive skin and mucous membrane blistering, scarring, and other systemic complications.
**Why the Correct Answer is Right**
In congenital dystrophic EB, mutations are typically found in the gene coding for collagen type VII, a protein that plays a vital role in anchoring the epidermis to the dermis. This gene is located on chromosome 3 (COL7A1) and encodes for the protein responsible for the formation of anchoring fibrils, which are essential for maintaining skin integrity. The absence or dysfunction of collagen type VII leads to the characteristic skin fragility and blistering observed in dystrophic EB.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as mutations in the gene coding for laminin 332 (LAMA3) are associated with junctional epidermolysis bullosa, not dystrophic EB.
**Option B:** This option is also incorrect as mutations in the gene coding for keratin 5 (KRT5) are associated with epidermolytic epidermolysis bullosa, a different subtype of EB.
**Option C:** This option is incorrect as mutations in the gene coding for integrin α6 (ITGA6) are associated with a rare form of EB, known as epidermolysis bullosa with pyloric atresia.
**Clinical Pearl / High-Yield Fact**
Dystrophic EB is a severe and often life-threatening condition that may require early skin grafting, pain management, and nutritional support to prevent complications.
**Correct Answer:** C. COL7A1