Filaggrin R501x and 2282del4 gene mutations and its tissue levels in patients with chronic plaque psoriasis

Background Psoriasis is a chronic inflammatory hyperproliferative disease. Psoriasis susceptibility locus 4 (PSORS4)-linked psoriasis to a region located at 1q21 chromosome, which contains the so-called epidermal differentiation complex, containing the filaggrin (FLG) gene. ObjectiveTo detect the FLG R501x and 2282del4 gene mutations and whether such mutations alter tissue FLG expression and are involved in the pathogenesis of psoriasis. Patients and methods Punch skin biopsies were taken from lesional, nonlesional skin of 30 patients with plaque psoriasis and normal skin of 20 healthy controls for FLG estimation by enzymelinked immunosorbant assay. Five milliliter venous blood was withdrawn from patients and controls for the detection of FLG gene mutation by PCR. Results FLG tissue levels were significantly lower in lesional skin compared with controls (P = 0.0001) and nonlesional skin (P= 0.0001). Both the R501x and 2282del4 FLG gene mutations were not statistically different between patients and controls (P = 0.804 and P= 0.236, respectively). Conclusion The FLG R501X and 2282del4 mutations, in Egyptians, are not associated with a higher risk of psoriasis development. Although the cutaneous FLG level was reduced in patients, it is unlikely that this reduction is a consequence of the studied mutations. The presence of varied terminal differentiation, due to abnormal or reduced FLG, may lead to increased susceptibility to a change in the skin barrier, therefore inducing the onset of psoriasis