130812821ENSG00000065618ENSMUSG00000025064Q9UMD9Q07563NM_130778NM_000494NM_007732NM_001290825NP_000485NP_001277754NP_031758Collagen XVII, previously called BP180, is a transmembrane protein which plays a critical role in maintaining the linkage between the intracellular and the extracellular structural elements involved in epidermal adhesion, identified by Diaz and colleagues in 1990.

Each 180 kD a-chain contains a globular intracellular domain of approximately 70 kDa, which interacts with beta4-integrin, plectin, and BP230 [12][13] and is necessary for the stable attachment of hemidesmosomes to keratin intermediate filaments.

The disorder caused by biallelic COL17A1 mutations and is called junctional epidermolysis bullosa, an autosomal recessive skin disease with variable clinical phenotypes.

Clinical hallmarks, in addition to blisters and erosions of the skin and mucous membranes, include nail dystrophy, loss of hair, and dental anomalies.

Collagen XVII also plays a role as an autoantigen in Bullous pemphigoid (BP) and herpes gestationis (HG), both acquired subepithelial blistering disorders.

[19][20] Most immunodominant epitopes lie within the NC16A domain,[21] and the binding of the autoantibodies perturbs adhesive functions of the collagen XVII, and this (together with inflammation-related processes) leads to epidermal-dermal separation and skin blistering.

[23] Another synonymous mutation (c.3156C>T) was proposed to introduce a cryptic donor site, resulting in aberrant splicing, a theory which subsequently was confirmed in several families with ERED from different countries.