Pretibial epidermolysis bullosa: compound heterozygous variants in a rare dystrophic epidermolysis bullosa subtype

Pretibial epidermolysis bullosa (PEB) is a rare subtype of dystrophic epidermolysis bullosa (DEB), characterized by trauma-induced blistering and scarring limited to the pretibial area. DEB results from monoallelic or biallelic variants in the COL7A1 gene, which encodes type VII collagen. PEB generally presents with milder symptoms than other DEB forms. We report a 50-year-old man with a 30-year history of asymptomatic erythematous patches and tense blisters on the pretibial areas, triggered by construction work and improving during vacations. Physical examination revealed bilateral erythematous plaques, tense bullae, crusted erosions, and nail dystrophy of the feet. Histology and EM showed subepidermal blisters and defects in anchoring fibrils. Genetic testing identified presumptive compound heterozygosity for 2 likely pathogenic COL7A1 variants: a previously reported missense variant (c.151C>G; p.Arg51Gly) and a novel frameshift variant (c.1752del; p.Ser585Valfs*30). Symptomatically management included protective dressings. The specific combination of variants in this patient has not been previously documented. This case underscores the relevance of diagnosing PEB and identifying novel COL7A1 variants, emphasizing the need for further research to understand genotype-phenotype correlations and explore treatment options.