The association of endoplasmic reticulum aminopeptidase-1 (ERAP-1) with Familial Mediterranean Fever (FMF).

BACKGROUND

The ERAP1 gene cleaves the receptors and reduces their ability to transmit chemical signals to the cell that affect the process of inflammation and, secondly, it cleaves many types of proteins into small peptides that are recognized by the immune system.

OBJECTIVE

ERAP-1 gene mutations may create a sensitivity for Familial Mediterranean Fever (FMF).

METHOD

We included 15 FMF patients with the M694 (+) mutation in the study in order to exclude patients without pyrin gene mutations and create a homogeneous study group. Fifteen patients with ulcerative colitis formed the control group.

RESULTS

There wasn't any case without ERAP-1 gene mutations. At least one mutation at exon 3 or exon 10 was found in all cases in both groups. There were 14 ERAP-1 gene mutations at exon 10 and 11 at exon 3 in patients with FMF. Interestingly, if there were ERAP-1 gene mutations at exon 3, a p.Arg127 Pro (c.380 G>C) mutation always existed for three FMF patients with polymorphic mutations at this exon. There were 11 ERAP-1 gene mutations at exon 10 and 12 gene mutations at exon 3 in patients with ulcerative colitis. Exon 3 mutations were usually single p.Arg127 Pro (c.380 G>C) mutations for 12 patients with ulcerative colitis as seen in the patients with FMF. The single mutation was always p.Ser453 Ser (c.1359T>C) for patients with ulcerative colitis at exon 10.

CONCLUSION

There are more ERAP-1 mutations in the FMF group in comparison to the ulcerative colitis group. So, there may be a strong susceptibility to ERAP-1 gene mutations in FMF patients according to our results. However, further studies with larger study and control groups are needed.