Autosomal dominant epidermolysis bullosa dystrophica: are the Cockayne-Touraine, the Pasini and the Bart-types different expressions of the same mutant gene?

Dominant dystrophic epidermolysis bullosa (Pasini) caused by a novel glycine substitution mutation in the type VII collagen gene (COL7A1)

A 12 y old girl with the albopapuloid variant (Pasini) of dominant dystrophic epidermolysis bullosa is studied. The albopapuloid lesions developed within the first year of life, contained milia and were associated with pruritus. Mutation detection of the COL7A1 gene revealed a G-->A transition at nucleotide position 6110 in the mutant allele converting a glycine to glutamic acid (G2037E). This report adds to the expanding database on COL7A1 mutations in dystrophic epidermolysis bullosa.

Clinical phenotype of Bart's syndrome seen in a family with dominant dystrophic epidermolysis bullosa

BACKGROUND

Bart's syndrome is one type of dominant dystrophic epidermolysis bullosa (EB). It is known that, in some familial cases of dominant dystrophic EB, the symptoms differ depending on the individual. We observed the way Bart's syndrome affected four generations in the same family. The proband was a newborn boy who showed congenital localized absence of skin (CLAS) and bullae on the anterior aspects of both legs. Histologically, the bullae were located subepidermally. The CLAS and bullae disappeared within 4 months after birth, leaving scars. His father retained scarring and scaling from the knees down along the anterior aspect of the legs, and the nails of the toes were either lacking or deformed. His paternal grandmother and great-grandmother also presented deformed nails of the toes, although they had not had CLAS or bullae on the legs at birth. The individuals in this family thus showed some heterogeneity depending on the sex: blistering and CLAS were seen on the legs soon after birth in the male family members, but the female members did not share this pattern of symptoms, suggesting that the expression of symptoms may differ depending on the sex of the affected individual.

Genetic linkage between the collagen type VII gene COL7A1 and pretibial epidermolysis bullosa with lichenoid features

Pretibial epidermolysis bullosa is a rare form of dominant dystrophic epidermolysis bullosa. The disease was diagnosed after considerable delay in a large Belgian family and was remarkable for its late age at onset and its misleading clinical presentation in the proband, which strongly resembled keratosis lichenoides chronica. Both recessively and dominantly inherited forms of dystrophic epidermolysis bullosa have been shown to be linked to the collagen type VII gene, COL7A1. Two-point linkage analysis with two intragenic polymorphisms (PvuII, AluI) in COL7A1 was performed. Strong genetic linkage between the disease in this family and COL7A1 was demonstrated by a lod score of 4.45 (theta = 0) for the AluI polymorphism. The observed intrafamilial variability of clinical phenotypes contradicts the presently proposed classification of dominantly inherited dystrophic epidermolysis bullosa.

Genetic Linkage Between the Collagen VII (COL7A1) Gene and the Autosomal Dominant Form of Dystrophic Epidermolysis Bullosa in Two Dutch Kindreds

Epidermolysis bullosa is a heterogeneous group of heritable blistering skin diseases affecting epidermis and the dermal-epidermal junction zone. Recently, genetic linkage to the type VII collagen gene (Z = 8.77; theta = 0.00) localized on chromosome 3p21 was shown in three Finnish families with the autosomal dominant form of dystrophic epidermolysis bullosa. Two Dutch kindreds with intrafamilial characteristics of both the Cockayne-Touraine type and Bart's syndrome of autosomal dominant dystrophic epidermolysis bullosa have been studied. Two-point linkage analysis in these two families with the COL7A1 marker revealed a combined lod score of Z = 6.08 at theta = 0.00. These data strongly suggest that the type VII collagen gene is the candidate gene in these Dutch pedigrees. At least two (Cockayne-Touraine and Bart) of the three subtypes of dominant dystrophic epidermolysis bullosa seem to represent different forms of expression of the same gene defect.

Glycosaminoglycans production by cultured skin fibroblasts from the Pasini and Cockayne-Touraine forms of dominant dystrophic epidermolysis bullosa

Qualitative and quantitative comparisons of glycosaminoglycans e (GAG) production were made on fibroblast lines cultured from the skin of six patients with the Pasini (albopapuloid) form of dominant dystrophic epidermolysis bullosa, six with the non-albopapuloid form (Cockayne-Touraine), eight lines from patients with simplex or recessive dystrophic epidermolysis bullosa and eight lines from normal individuals. A reasonable match of donor age and gender, site, and passage number was achieved. Contrary to an earlier report, the lines from the Pasini group were unexceptional in the amount of GAG they secreted and the proportions of sulfated and nonsulfated GAG showed no consistent difference from the Cockayne-Touraine or control lines. The Pasini lines secreted 77 +/- 18 (SEM) microgram GAG-uronic acid per 10(7) cells and the Cockayne-Touraine lines 81 +/- 12 micrograms at equivalent cells densities. Sulfated GAG represented averages of 19 +/- 4+ in Pasini lines, 17 +/- 5% in Cockayne-Touraine, and 14 +/- 3% in controls. These findings are consistent with current views of albopapuloid lesions as an unreliable clinical sign in epidermolysis bullosa and bring into question the validity of the Pasini entity.