Recessive epidermolysis bullosa simplex due to EXPH5 variants: case series of a rare subtype with multiple faces

What are the clinical and diagnostic characteristics of patients with recessive epidermolysis bullosa simplex due to pathogenic EXPH5 variants (REBS-EXPH5)? Our case series offers comprehensive characteristics, including a phenotype evolving from widespread blisters and erosions to pigmentary changes over time. Diagnostic clues for a diagnosis of REBS-EXPH5 include prominent keratin filament clumping and increased numbers of intracellular vesicles and mitochondria as seen by transmission electron microscopy and the absence of exophilin-5 immunostaining. The identification of truncating EXPH5 variants in exon 6 through genome diagnostics provides confirmation of the diagnosis.