1Novel MEFV transcripts in Familial Mediterranean fever patients and controls

Familial Mediterranean Fever and Multiple Sclerosis Successfully Treated With Interferon Beta-1a: A Case Report

Multiple sclerosis (MS) is the most common demyelinating disease in Turkey while familial Mediterranean fever (FMF) is the most common periodic fever syndrome worldwide. In this article, we report a 37-year-old male patient admitted with complaint of difficulty in walking. He had been taking colchicine at admission for 27 years. Despite this therapy, he had been experiencing twice monthly severe FMF attacks. After systemic and neurological examinations, laboratory tests and cranial and spinal magnetic resonance imaging, he was diagnosed as MS. Interferon (IFN) beta-1a was initiated three times/weekly subcutaneously for MS treatment. He stopped colchicine treatment after five months of IFN treatment because he did not suffer from any FMF attacks. He is still attack free for both diseases for a follow-up duration of 12 months. IFN beta is one of the most preferred agents for MS treatment but not one of the agents used for the treatment of FMF. Interferon beta can be a treatment of choice in patients with coincident FMF and MS and can be used in colchicine-resistant patients after being studied in systematic clinical studies.

Alternatively spliced MEFV transcript lacking exon 2 and its protein isoform pyrin-2d implies an epigenetic regulation of the gene in inflammatory cell culture models

The function of gene body DNA methylation in alternative splicing, and its relation to disease pathogenesis is not fully elucidated. The gene for familial Mediterranean fever (MEFV) encodes the pyrin protein and contains a 998 bp CpG island, covering the second exon, which is differentially methylated in FMF patients compared to healthy controls. Our further observation of increased exon 2-spliced MEFV transcript in leukocytes of FMF patients provoked us to test the role of exon methylation in alternative splicing using inflammatory cell culture models. First, in vitro exon methylation triggered an increased level of exon 2 exclusion using a splicing cassette in a promyelocytic leukemia cell line (HL-60). HL-60 cells subjected to methylating and demethylating agents, as well as cells differentiated to neutrophil-like cells, exhibited different levels of spliced/unspliced transcripts. We observed increased levels of spliced transcripts in neutrophil-like (p = 0.0005), activated (p = 0.0034) and methylated cells (p < 0.0001), whereas decreased levels in demethylated cells (p = 0.0126) compared to control untreated HL-60 cells. We also showed that the protein isoform of pyrin lacking the exon 2 has an adverse subcellular localization in neutrophil-like cells. Therefore, it remains in the cytoplasm rather than the nucleus. This may point to an epigenetic involvement in an important inflammatory gene.

Guidelines for the genetic diagnosis of hereditary recurrent fevers

Hereditary recurrent fevers (HRFs) are a group of monogenic autoinflammatory diseases characterised by recurrent bouts of fever and serosal inflammation that are caused by pathogenic variants in genes important for the regulation of innate immunity. Discovery of the molecular defects responsible for these diseases has initiated genetic diagnostics in many countries around the world, including the Middle East, Europe, USA, Japan and Australia. However, diverse testing methods and reporting practices are employed and there is a clear need for consensus guidelines for HRF genetic testing.

Draft guidelines were prepared based on current practice deduced from previous HRF external quality assurance schemes and data from the literature. The draft document was disseminated through the European Molecular Genetics Quality Network for broader consultation and amendment. A workshop was held in Bruges (Belgium) on 18 and 19 September 2011 to ratify the draft and obtain a final consensus document. An agreed set of best practice guidelines was proposed for genetic diagnostic testing of HRFs, for reporting the genetic results and for defining their clinical significance.

Analysis of MEFV exon methylation and expression patterns in familial Mediterranean fever

BACKGROUND

MEFV mutations and decreased expression level of the gene are related to FMF pathology. DNA methylation at CpG islands is a well-known mechanism for transcriptional silencing. MEFV has a CpG island, spanning a part of the first intron and the whole of the second exon of the gene covering 998 bp region. Here, we tested the hypothesis that the MEFV transcript level in FMF patients correlates with its methylation level, and methylation, by allowing transcription silencing, has a role in FMF ethiopathogenesis.

METHODS

The study group was composed of pediatric FMF patients (N = 51) and age-gender matched healthy controls (N = 21). The relative expression level of MEFV was assessed via quantitative real-time PCR (qRT-PCR) and bisulfite sequencing (BS) was performed to analyse the methylation level quantitatively.

RESULTS

MEFV expression in FMF patients were decreased compared to healthy controls (P = 0.031). Methylation level of exon 2 of MEFV was found to be slightly higher in FMF patients compared to healthy controls (76% versus 74%) (P = 0.049). The expression level of the MEFV was negatively correlated with the methylation level of the CpG island in both FMF and healthy controls groups (cor = -0.29, P = 0.041) but more so in the FMF only group (cor = -0.36, P = 0.035).

CONCLUSIONS

In this study, the relation between reduced MEFV expression level and FMF was confirmed. Observed slight increase in methylation in FMF patients, and correlation of methylation with expression might be indicative of its role in FMF, however a larger dataset is needed to confirm our preliminary findings.

Increased expression of exon 2 deleted MEFV transcript in familial Mediterranean fever patients

A defect in MEFV gene expression regulation has been implicated in familial Mediterranean fever (FMF) etiopathophysiology. Here we show significantly higher expression level in second exon lacking MEFV transcript in FMF patients compared with healthy controls (P=0.026). Our results also point out a possible role of exon 2 deleted MEFV transcript in FMF pathogenesis.