In congenital dystrophic variety of epidermolysis bullosa, mutation is seen in the gene coiling for :

Ans. b. Collagen type 7 (Ref: Fitzpatrick k 7/e p494-499; Rooks 8/e p40.51-40. 56, 13. 19. 10, 12-10.28; Roxburgh 17/e p90-91]In a congenital dystrophic variety of epidermolysis bullosa, mutation is seen in the gene coding for collagen type 7.DisorderDirect Immunofluorescence Pattern DepositsTarget antigenPemphigus vulgaris Intercellular, intraepidermal IgG, fish net#esmogiein 3Pemphigus foliaceus Intercellular, intraepidermal IgG, fish netDesmoglein 1Paraneoplastic pemphigusIntercellular and subepidermal IgG, fish netPlakins (desmoplakin, envoplakin, periplakin, BP 230)Bullous pemphigoidBasement membrane zone IgG, linearBP23G > BP180Herpes gestationalBasement membrane zone IgG, linearBP23G > BP180Dermatitis herpetiformis Dermal papillae IgA, granular Epidermal tissue trnasglutami naseLinear IgA diseaseBasement membrane zone IgA, linearBP180Epidermolysis bullosa dystrophicaBasement membrane zone IgG, linearCollagen VII(anchoring fibril)Epidermolysis Bullosa*Epidermolysis bullosa congenita is inherited genodermatoses (genetic disorder)*Epidermolysis bullosa acquisita is a sporadic autoimmune bullous disease*Characterized by the skin and related epithelial tissue break and blisters as a result of minor trauma.Pathology:* Alpha chain of collagen 7 is defective in EB acquisita and EB dystrophicClinical Features:*Skin fragility, spontaneous or trauma-induced non-inflammatory tense bulla over trauma-prone surfaces such as sacral area, elbow, knee, back of hands.*Lesions heal with scarring, scaling, crust formation or erosions and pearl-like milia cyst formationDiagnosis:Direct immune electron microscopy (gold standard) and direct immunofluorescence (DIF) of perilesional skin show intense, linear, homogenous fluorescent band of IgG and C3 at the dermoepidermal junction.