Ailesel Akdeniz ateşi, gut ve erişkin still hastalarında MEFV mutasyon analizi

The "autoinflammatory" term is first defined and developed in 1999 by a group of researcher who were studying hereditary periodic fever syndromes. The main cause of the syndromes is mutations/variations in genes involved in innate immunity and their alteration of the signaling or cytokine activation pathways. Familial Mediterranean fever (FMF, OMIM ID: 249100 and 134610) is one of the most common and best characterized inflammatory diseases that is inherited autosomal recessively and characterized by recurrent attacks of fever, abdominal pain, rashes, and arthritis while amyloidosis is the most severe complication of the autoinflammatory disorder. Gout is common inflammatory arthritis caused by hyperuricemia and the deposition of uric acid crystals in tissues and fluids within the body which results with metabolic, cardiovascular and renal morbidity especially in men over age of 40. Adult-Onset Still's Disease (AOSD) is a rare inflammatory disorder of unknown etiology and characterized by daily spiking fever, arthritis and rash. MEFV, MEditerranean FeVer gene is the first autoinflammatory gene that is introduced as a candidate gene for FMF. To date, 305 sequence variations are identified on MEFV gene. Still new mutations/variations and their association with FMF are understudied. Mutations/variations are located in exons 1, 2, 3, 5, 9 and 10 of MEFV. The majority of the mutations/variations are missense changes and clustering in exons 2 and 10. There are five common mutations/variations; V726A, M694V, M694I, M680I in exons 10 and E148Q in exon 2. MEFV transcripts encode a 781 amino acids protein called Pyrin or Marenostrin (P/M). The main function of P/M protein is the regulation of caspase-1 activation, relatively interleukin-1β (IL-1β) production. The association between FMF and MEFV gene mutations/variations is well established in the previous studies, still the existence of patients without mutations/variations and P/M role were not clarified. The aim of this study was to examine the specificity of MEFV gene to FMF or to general inflammatory pathway by comparing with other autoinflammatory diseases. MEFV exon 2 and 10 variations were explored in a group of FMF (N=75), Gout (N=30) and AOSD (N=28) patients and compared the frequencies between disease groups and healthy controls (N=54). MEFV gene product P/M is indicated to have a role in inflammatory pathway. The aim of the protein studies was the quantification of P/M levels in FMF (N=22) patients compared to healthy controls (N=9). DNA and protein samples were obtained from whole blood. We first compared all mutations/variations between the patient and HC groups. MEFV gene mutations/variations were detected in 73 (97.3%) patients in FMF group, 21 (75%) in AOSD, 20 (66.6%) in Gout and 35 (64.8%) in HC group. MEFV mutations/variations were detected in 16.2% of alleles in FMF, 6.8% in Gout, 5.4% in AOSD patients and 7% in HC. The difference in the frequency of the MEFV mutations/variations between the patient groups and control group was statistically significant (p=<0.0001). The common haplotype A165A-D102D-G138G was observed frequently in all groups, but the frequency was higher in FMF group (61.8%) compared to Gout (30%), AOSD (22.6%) and HC (33.6%) (non-significant). One of the most common variations E148Q in exon 2 was observed at a frequency quite similarly between groups. The frequencies were 5.3%, 5.0%, 7.1%, 5.6% in FMF, AOSD, Gout patients and healthy controls, respectively (non-significant). In exon 2, only R202Q variation was found to be more frequent in FMF patients (42%) compared to other groups (19-25%) (FH: p<0.0001, FG: p=0.0266, FS: p=0.0032). Out of 16.2% of all observed mutations/variations in FMF, R202Q was observed in 2.2%, whereas E148Q in 0.3%. There was also significant difference in pathogenic mutations/variations between FMF and other groups. Out of 5.2% of all alleles, they were observed 3.5% in FMF, whereas 0,5-0,6% in other groups. Within these pathogenic mutations/variations, out of 19.7%, only E148Q (4.6%) and M694V (11.2%) were observed in all groups. The most prominent pathogenic mutation/variation was M694V. It was observed 8.9% in FMF, 1.3% in Gout, 0.4% in AOSD and 0.6% in healthy controls as being the most frequent mutations/variations (p=<0.0001). As a further aspect, increased M694V frequency in Gout and AOSD patients compared to HC requires further analysis. Second part of this study, we wanted to investigate the quantification of P/M levels in FMF (N=22) patients compared to healthy controls (N=9). Our preliminary results indicate approximately two fold decrease of P/M levels in FMF patients compared to HC group (p=0.3920), which is the opposite of the previous results. To investigate the relationship between mutations/variations and P/M levels, MEFV mutation/variation analysis were also performed in protein study group. The allele frequencies of M694V in FMF and HC were 34.1% and 5.6%, respectively (p=0.0247). E148Q, R202Q and R761H were also observed in both groups, however NS. The average P/M quantity of the patients carrying M694V mutation/variation was 0.23, whereas non-carriers had 0.33. One of the FMF patients was in her/his attack period when the sample was collected and the P/M level was highest even though he/she was not M694V mutation/variation carrier. We have observed much higher P/M level and total mutation/variation carrying allele in attack patient compared to attack free patients. The protein study requires optimization with enlarged sample sizes and replicated for more accurate statistical results.