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 de lay in a large Belgian family and was remarkable for its late age at o nset and its misleading clinical presentation in the proband, which st rongly resembled keratosis lichenoides chronica. Both recessively and dominantly inherited forms of dystrophic epidermolysis bullosa have be en shown to be linked to the collagen type VII gene, COL7A1. Two-point linkage analysis with two intragenic polymorphisms (PvuII, AluI) in C OL7A1. was performed. Strong genetic linkage between the disease in th is family and COL7A1 was demonstrated by a led score of 4.45 (theta = 0) for the AluI polymorphism. The observed intrafamilial variability o f clinical phenotypes contradicts the presently proposed classificatio n of dominantly inherited dystrophic epidermolysis bullosa.