Pretibial dystrophic epidermolysis bullosa, recessiveQ82.8

Kuske H, 1946

Pretibial dystrophic epidermolysis bullosa is characterized by recurrent, frequently pruritic, even severely pruritic blistering and scarring, mainly in the lower extremity (especially shins). The lesions show lichenoid, also hyperkeratotic features ((Naeyaert et al. 1995)). Furthermore, scarring is found, also with the formation of whitish plaques. The clinical picture of a chronic prurigo can develop if the disease is present for several years. The nails are dystrophic.

Heterozygous mutation in the COL7A1 gene (G2623C; 120120.0007) (Lee et al. 1993; Naeyaert et al. 1995; Christiano et al. 1995). Betts et al. (1999) described a recessively inherited COL7A1 splice site mutation , which impairs procollagen VII processing (120120,0021). Gardella et al (2002) described a heterozygous mutation in the COL7A1 gene in this condition (P1699L, 120120.0029; IVSAS2-1G-C, 120120.0030).

Onset in late childhood (after the age of 10). Blistering is triggered by trivial skin trauma.

One affected individual in a family had albopapuloid skin lesions resembling those of the Pasini form of DEB (reviewed in 131750).

Lee et al (1993) reported 19 patients from 13 Taiwanese families with dystrophic epidermolysis bullosa characterized by blisters and scars affecting mainly the area in front of the tibia. Inheritance was autosomal dominant in 10 families, siblings were affected in 2 families, and there was a sporadic case in 1 family. All affected individuals had nail dystrophies. Furthermore, pruritus was a common feature. In 4 affected individuals, pruritus resulted in a significant disturbance of well-being. Eight patients had skin lesions exclusively on the lower extremity. All other affected individuals also had porcelain-like whitish plaques (albopapuloid) or hypertrophic scars elsewhere. Compared with normal control subjects, electron microscopic anchoring fibrils were rudimentary and sparser in both lesional and normal skin. They did not differ markedly from those seen in other types of dystrophic DEB.

Christiano et al (1995) studied one of the families reported by Lee et al (1993). The clinical phenotype was characterized by pretibial blisters that developed into prurigo-like hyperkeratotic lesions. The lesions occurred predominantly in the pubic region, omitting the knees and other skin areas. Other clinical features included nail dystrophy, albopapuloid skin lesions, and hypertrophic scars without pretibial dominance.

Naeyaert et al (1995) described a large Belgian family with pretibial DEB. The clinical picture of the proband showed a lichenoid aspect and strongly resembled keratosis lichenoides chronica. In the affected family members, the disease appeared after the age of 10 years.

Electron microscopy: cleft formation in the sublamina densa zone under the basement membrane, decreased number of anchoring fibrils at the dermal-epidermal interface, hypotrophic anchoring fibrils.

Direct immunofluorescence: Decreased staining for collagen VII.

Both autosomal dominant and recessive inheritance can occur