The molecular genetics of basement membrane diseases.

BACKGROUND

Keratin filaments, hemidesmosomes, anchoring filaments, the lamina densa, and anchoring fibrils each function to maintain different levels of basement membrane cohesion.

OBSERVATIONS

Keratin 5 or 14 mutations are present in epidemiolysis bullosa simplex. Herlitz junctional epidermolysis bullosa is characterized by defects of the anchoring filament protein kalinin (alternatively known as nicein). Mutations of the type VII collagen gene appear to be the primary cause of dominant and recessive dystrophic epidermolysis bullosa. Two hemidesmosomal components are the bullous pemphigoid (BP) antigens: BP230 shows homology to desmoplakin, a desmosomal component; BP180 contains extracellular collagen domains. The autoantigens in cicatricial pemphigiod and IgA-mediated autoimmune diseases are less well understood. Type IV collagen chains are affected in Alport's and Goodpasture's syndromes.

CONCLUSIONS

New diagnostic and therapeutic techniques based on these genetic/biochemical advances are currently being developed.