In congenital dystrophic variety of epidermolysisbullosa, mutation is seen in the gene conding for:
**Core Concept**
The congenital dystrophic variety of epidermolysis bullosa (EB) is a severe form of EB characterized by the formation of blisters due to a defect in the anchoring fibrils that connect the epidermis to the dermis. This condition is caused by mutations in a specific gene that codes for a protein crucial for the formation and stability of these anchoring fibrils.
**Why the Correct Answer is Right**
The correct answer is related to the gene that encodes for collagen type VII, a key protein in the anchoring fibrils. Mutations in this gene lead to the production of a dysfunctional protein, resulting in the loss of anchoring fibrils and the characteristic blistering seen in dystrophic EB. This is due to the crucial role of collagen type VII in providing mechanical strength to the anchoring fibrils and maintaining the integrity of the dermal-epidermal junction.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as the gene responsible for dystrophic EB is not related to the production of keratin proteins, which are crucial for the structure and strength of the epidermis.
**Option B:** This option is incorrect as the gene responsible for dystrophic EB is not related to the production of laminin proteins, which are involved in the formation of the basement membrane but not directly involved in the anchoring fibrils.
**Option C:** This option is incorrect as the gene responsible for dystrophic EB is not related to the production of integrin proteins, which are involved in cell-cell and cell-matrix interactions but not directly involved in the anchoring fibrils.
**Clinical Pearl / High-Yield Fact**
A key clinical feature of dystrophic EB is the presence of atrophic scarring, which results from the repeated blistering and subsequent healing of the skin. This can lead to significant morbidity and mortality in affected individuals.
**Correct Answer:** C. The correct answer is C, as the gene responsible for the congenital dystrophic variety of epidermolysis bullosa is the gene that codes for collagen type VII.