[Purpura pigmentosa progressiva in type III cryoglobulinemia and tartrazine intolerance. A follow-up over 20 years].

A 58 year old patient with hepatitis virus C (HCV) infection had a secondary polyclonal IgG-IgM cryoglobulinemia with a benign 20 year course. Clinically the patient suffered from progressive pigmented purpura (PPP). Histologic evaluation revealed a lymphocytic vasculitis.

A combination of a common splice site mutation and a frameshift mutation in the COL7A1 gene: absence of functional collagen VII in keratinocytes and skin.

We describe a patient with severe generalized dystrophic epidermolysis bullosa (EBD) and a novel combination of compound heterozygous mutations in the COL7A1 gene. The maternal mutation was an A-to-G transition (425-A --> G) at position -2 of the donor splice site within exon 3 that causes aberrant splicing of two abnormal transcripts. One includes intron 3, and one excludes both exon 3 and intron 3.

Immunohistochemical and mutation analyses demonstrate that procollagen VII is processed to collagen VII through removal of the NC-2 domain.

Collagen VII is the major structural constituent of anchoring fibrils in the skin. It is synthesized as a procollagen that is larger than the collagen deposited in the tissue. In this study, we investigated the conversion of procollagen VII to collagen VII in human skin and in cutaneous cells in vitro and identified the propeptide using domain-specific antibodies.

Collagen VII in severe recessive dystrophic epidermolysis bullosa: expression of mRNA but lack of intact protein product in skin and cutaneous cells in vitro.

The collagen VII gene, COL7A1, is the candidate gene for both the recessive and dominant forms of dystrophic epidermolysis bullosa (EBD). Collagen VII is a structural protein of the anchoring fibrils, which are rudimentary or altered in several subtypes of EBD. In severe recessive mutilating EBD, anchoring fibrils and collagen VII are not detectable in skin of most patients.