Identification of a novel variant in the LAMB3 gene in a patient with a distinct junctional epidermolysis bullosa laryngo-onycho-cutaneous syndrome phenotype

Junctional epidermolysis bullosa (JEB) represents a rare mechanobullous genodermatosis, characterized by fragility and blister formation of the skin and mucous membranes. Within the JEB spectrum, laryngo-onycho-cutaneous (LOC) syndrome is a rare subtype that manifests with excess granulation tissue of the eyes, nails, skin, and larynx. Thus far, the LOC subtype has been linked predominantly to mutations in LAMA3, disrupting the epidermal basement membrane zone. We present a unique case of a congenitally affected female with numerous cutaneous eroded plaques, oral ulcers, nail dystrophy, and laryngeal involvement phenotypically consistent with the rare JEB LOC subtype. Genetic testing revealed a previously unreported homozygous variant in the LAMB3 gene (p.C316Y) highlighting a novel variant in the LAMB3 gene and its association with the LOC phenotype of JEB.