Lysyl oxidase‐like‐2 mutations and reduced mRNA and protein expression in mid‐dermal elastolysis

BACKGROUND: Mid-dermal elastolysis (MDE) is a rare skin condition, characterized by selective loss of elastic fibres in the mid dermis. The pathogenesis of MDE is still unclear. AIM: To investigate expression of lysyl oxidase-like 2 (LOXL2) in a reasonable sample of patients with MDE and to search for mutations in LOXL2. METHODS: We investigated archived lesional tissue of 13 patients with MDE and skin tissue samples of 10 sex- and age-matched healthy controls (HCs). Gene and protein expression of LOXL2 was investigated using real-time reverse-transcription PCR and immunohistochemistry. Mutation analysis was performed using the Sanger method. RESULTS: We observed decreased LOXL2 mRNA expression in lesional skin of patients with MDE (0.48 ± 0.16) compared with healthy skin of the same patients (1.5 ± 0.51) and normal skin of HCs (1.9 ± 0.13). Compared with healthy patient skin (epidermis 2.38 ± 1.6, dermis 1.2 ± 1), LOXL2 protein expression in lesional patient skin (epidermis 1.1 ± 0.7, dermis 0.3 ± 0.45) was significantly decreased (P  C, c.1022 C>T, and c.1025 G>A, respectively), and one of them also had a mutation in the splice region of intron 11/exon 12 (IVS11-1 G>A). Of the remaining two patients, one had a mutation in exon 3 (T1391), and the other had a mutation in exon 11 (C663Y). CONCLUSIONS: Our present data suggest that decreased elastin renewal due to LOXL2 mutations and consecutive reduced LOXL2 expression contribute to the pathogenesis of MDE.