Gereç ve Yöntem: Klinik olarak FMF tanısı almış, akraba olmayan üç fertli bir aile literatür eşliğinde sunulmuştur. Aile bireylerinin DNA’sından PCR tekniği kullanımı ile MEFV geninin tüm ekzonlarının çoğaltılmasından sonra, aile bireyleri için MEFV geninin tüm ekzom dizi analizi yapıldı.

Bulgular: Mutasyona uğramış bir Pyrin/Marenostrin protein oluşturan, MEFV geninin 1. Ekzonu kodlama bölgesinde yer alan A89T (p.Ala89Thr, c.265G>A) heterozigot mutasyonu görüldü (hem probandda, hemde onun annesinde). Bu tespit edilen mutasyon ekzon 1 de nadir görülen bir mutasyondur.

Sonuç: Bildiğimiz kadarıyla bu bildirilen ilk Türk ailesi ve dünyada bildirilen ikinci vakadır. Biz şu anki makalenin hastalığın daha açık anlaşılması için ve FMF patogenezisi üzerinde ilerleyen dönemlerde yapılacak olan çalışmalar için önemli bilgi sağlayacağını düşünüyoruz.

Before the colchisin treatment, renal amyloidosis (the most severe complication of FMF) was the reason of mortality in these cases⁴. The FMF gene (MEFV) was identified in 1997 and it consists of 10 exons that placed on chromosome 16p13.3. MEFV is liable for the disease and its product, pyrin or marenostrin consisting of 781 amino acids that plays a crucial role in the arrangement of the inflammatory response^2,5. Marenostrin/pyrin (M/P) the protein product of the MEFV gene, interface with the ASC (apoptosis associated speck-like protein with a caspase-recruitment domain (CARD)⁶. Pyrin consist in differential isoforms, involving M/P-fl and the M/P-d2. ASC is coded by the PYCARD gene and it has functions to arrange inflammatory and apoptotic signalling in multiprotein complexes named ‘inflammasomes^6,7. ASC and pyrin interact entirely their PyD domains. It was reported that both pyrin and ASC proteins regulates the response of cellular inflammation either inducers or suppressors in different studies^8,9.

Autosomal recessive pattern of inheritance is usually evident but the studies have reported that cases with just one heterozygous mutation described by routine screening can be prescribed colchicine in the existence of clinical symptoms^10,11. In 2009, Marek-Yagel et al., researched the molecular and clinical characteristics of heterozygous FMF cases. Their research showed that even though the heterozygotes tend to have a mild disease, the disease could not be discriminated from that of homozygous cases¹². As noted previously made in similar studies, this syndrome shows a heterogeneous genetic basis^10-13.

Selected mutation analysis approves the diagnosis in most cases with classic FMF. The sequence analysis may be required for patients with atypical FMF or mild clinical presentation. Molecular diagnostic testing for FMF is a non-invasive and specific technique, which can be used for the right diagnosis before the occurrence of the all clinical symptoms. More than 314 gene mutations and polymorphisms have been discovered in the MEFV gene to date¹⁴. Still new mutations are identified and their relationship with FMF clinic is investigated¹⁵.

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Figure 1: Family Pedigree of proband and nucleotide sequence of exon 1 of the MEFV gene showing a single base substitution in our patient, A89T (p.Ala89Thr, c.265G>A).

Our patient didn't have a brother or a sister and clinically diagnosed with FMF two years ago. Our investigation indicated that in addition to the proband, her mother had clinical findings with FMF and we detected the same mutation, too. Proband’s father had no complaints with FMF. According to family history, there are no clinical symptomes of the disease in sisters and brothers of the probands’ parents (Figure 1). But it was reported us by probands’ mother, there was an abdominal pain in the probands grandfather. Because he has passed away, the genetic analaysis of patient was not performed for MEFV gene. Despite there was no clinical symptomes of the disease in probans’ grandmother, we invited the grandmother to apply the clinics. Because the probands’ grandmother did not apply the clinics because of the geographical reason, the mutation analysis of the grandmother was not done for MEFV gene.

The proband had fever, abdominal pain, chest pain, arthritis but no family history of FMF. Also there was an appendectomy story with our patient. The recurrency of the attack was once a month. She didn’t use colchicine regularly. Clinical data of the patients are given in Table 1.

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Table 1: Clinical data of the proband and her family

This family has been under clinical follow-up especially for their complaints and will be periodically checked for the parameters such as erythrocyte-sedimentation rate, C-reactive protein, CBC (complete blood count), SAA (systemic amyloid AA protein) that can be associated with inflammation.

ASC is an essential adaptor protein in the inflammatory pathway and interacts with marenostrin which is the key component and defective in FMF. There are several studies on this subject in the literature. In a recent study, Nalbantoglu et all., demonstrated that ASC mRNA expression was up-regulated in patients with MEFV mutations free of mutation type in Caucasian FMF patients¹⁶. Cazeneuve and his friends⁷ investigated the subcellular localisation of marenostrin isoforms with the patients who had MEFV mutations. A89T mutation was described in one patient of Armenian origin who had FMF and it is localised at the PYD domain. This domain is a protein–protein interaction domain in pyrin encoded by the first MEFV exon. A89T mutation was studied because of it directly interacts with the protein–protein interaction. To identify the effects of the MEFV mutations on the subcellular localisation of pyrin isoforms, the researchers expressed normal or mutated pyrin-fl or -d2 in HeLa cells in the absence or existence of ASC. At the end of the study, the results revealed that the functional result of the FMF related mutations are probably unrelated to a mislocalisation of the mutant pyrin even if the existence of its connective partner ASC¹⁷.

Due to A89T was very rare, we thought that when the number of individuals having this mutation increased, the effects of the mutation will be understood more easily. Also this mutation may ensure significant knowledges for further researches on FMF pathogenesis and particularly genotype-phenotype association studies.

The majority of FMF cases are larger in Eastern Mediterranean populations. The Turkish population with more than 79 million inhabitants have important number of FMF patients in the world. The prevalence of FMF is 1:500–1:1000 in Anatolia and the carrier frequency is as high as 1/5 among Turks². Thus, it is an obligatory to have more exact data about the FMF for more efficient public health services. In our study, we reported a rare mutation of the MEFV gene from Turkish family. Additionally in our previously performed studies, we identified two new mutations that also appear very rare^18-20. As shown, because of the MEFV heterogenity in Turkish FMF cases, larger serial analyses are necessary to define the distribution of MEFV mutations and to explore genotype-phenotype associations. Several studies related to newborn screening with FMF were done as yet²¹ and this issue will be discussed further in the coming period. In this study, we purposed to contribute to a rare A89T mutation and its clinical features accompanied with literature.

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2) Tunca M, Akar S, Onen F, et al. Turkish FMF Study Group. Familial Mediterranean fever (FMF) in Turkey: Results of a nationwide multicenter study. Medicine (Baltimore) 2005; 84: 1-11.

3) Ben-Chetrit E, Touitou I. Familial mediterranean fever in the world. Arthritis Rheum 2009; 61: 1447-1453

4) Ben-Chetrit E. Familial Mediterranean fever (FMF) and renal AA amyloidosis–phenotype–genotype correlation, treatment and prognosis. J Nephrol. 2003;16: 431-434

5) The International FMF Consortium. Ancient missense mutations in a new member of the RoRet gene family are likely to cause familial Mediterranean fever. Cell 1997; 7: 1317-1325

6) Taniguchi S, Sagara J. Regulatory molecules involved in inflammasome formation with special reference to a key mediator protein, ASC. Semin Immunopathol 2007; 29: 231-238.

7) Cazeneuve C, Papin S, Je´ru I, et al. Subcellular localisation of marenostrin/pyrin isoforms carrying the most common mutations involved in familial Mediterranean fever in the presence or absence of its binding partner ASC, J Med Genet 2003; 41:e24

8) Martinon, F, Burns K, Tschopp J. The inflammasome: A molecular platform triggering activation of inflammatory caspases and processing of proILbeta. Mol Cell 2002;10: 417-426

9) Yu JW, Wu J, Zhang Z, et al. Cryopyrin and pyrin activate caspase-1, but not NF-kB, via ASC oligomerization. Cell Death Differ 2006; 13: 236-249.

10) Ozen S. Changing concepts in familial Mediterranean fever: Is it possible to have an autosomal-recessive disease with only one mutation? Arthritis Rheum 2009; 60: 1575-1577.

11) Moradian MM, Sarkisian T, Ajrapetyan H, et al. Genotype-phenotype studies in a large cohort of Armenian patients with familial Mediterranean fever suggest clinical disease with heterozygous MEFV mutations. J Hum Genet 2010; 55: 389-393.

12) Sönmez E, Batu ED, Özen S. Familial Mediterranean fever: Current perspectives. Journal of Inflammation Research 2016; 9: 13-20.

13) Booty MG, Chae JJ, Masters SL, et al. Familial Mediterranean fever with a single MEFV mutation: Where is the second hit? Arthritis Rheum 2009; 60: 1851-1861

14) Infevers 2016. Accessed 16 May 2016 [http://fmf.igh.cnrs.fr/ISSAID/infevers//

15) Eroz R, Dogan M, Kocabay K. A novel mutation K447m (P.Lys447met, C.1340 A>T) identified in exon 4 of the MEFV gene. Genetic Counselling 2016; 27: 525-528.

16) Nalbantoglu S, Tanyolac B, Berdeli A. Apoptosis-associated speck-like protein containing a CARD (ASC) expression profiles in familial Mediterranean fever (FMF) patients with different MEFV mutation patterns Scand J Rheumatol 2013; 42: 159-162.

17) Richards N, Schaner P, Diaz A, et al. Interaction between pyrin and the apoptotic speck protein (ASC) modulates ASC-induced apoptosis. J Biol Chem 2001; 276: 39320-3929.

18) Eroz R, Dogan M, Yuce H, et al. A Novel Deletion Mutation 334-335 DelG (P.Glu112fs, C.334-335delg) Identified in Exon 2 of The MEFV Gene Associated with Familial Mediterranean Fever, Congress abstract,14. Ulusal Tıbbi Biyoloji ve Genetik Kongresi 27 – 30 Ekim 2015 Ölüdeniz /Fethiye

19) Dogan M, Eroz R, Yuce H, et al. A Turkish family with S288y (P.Ser863tyr, C.863 C>A) mutation on the MEFV gene, congress abstract, 14. Ulusal Tıbbi Biyoloji ve Genetik Kongresi 27 – 30 Ekim 2015 Ölüdeniz /Fethiye

20) Eroz R, Dogan M, Yuce H, et al. A Turkish family with 761_764dupCCGC(p.Asn256Argfs70,c.761_764dupCCG). mutation on the MEFV gene. Erciyes Medical Journal 2016; 38.

21) Oztuzcu S, Ulasli M, Ergun S, et al. Screening of common and novel familial mediterranean fever mutations in south-east part of Turkey. Mol Biol Rep 2014; 41: 2601-2607.