A decision tree for genetic diagnosis of hereditary periodic fever in unselected patients

BACKGROUND: The diagnostic value of molecular analysis of the familial Mediterranean fever (FMF) gene (Mediterranean fever (MEFV)) has been well established only in patients selected on the basis of ethnic background or clinical criteria. Genetic diagnosis for other hereditary periodic fever syndromes has been poorly evaluated. OBJECTIVE: To determine the diagnostic contribution of genetic tests for hereditary periodic syndromes in a large, unselected series of patients. METHODS: A retrospective study was conducted on 1941 patients referred to us for FMF genetic tests between 1997 and 2005. MEFV genotypes were compared with clinical data to appraise criteria for FMF diagnosis. Genetic tests for tumour necrosis factor receptor‐associated periodic syndrome (TRAPS), hyperimmunoglobulinaemia D syndrome (HIDS) and cryopyrin‐associated periodic syndromes (CAPS) were also reviewed. RESULTS: 71% of the 1574 patients with enough data had a clinical diagnosis of FMF according to the widely used Israeli criteria. Two MEFV mutations were found in only 409 patients of this subgroup (sensitivity = 37%) and in 15 (3.3%) of the patients with an improbable clinical diagnosis of FMF (specificity = 97%). Molecular diagnosis for alternate hereditary periodic syndromes was carried out in 456 of the patients having a non‐conclusive FMF genetic test. A positive diagnosis was obtained in 31 of these patients (TRAPS (n = 19), HIDS (n = 4) and CAPS (n = 8)). CONCLUSIONS: First‐line MEFV mutation screening in patients with clinically typical FMF may be appropriate only in particular areas. To optimise genetic diagnosis, we propose a decision tree, which, with the advice of an expert practitioner, could help redirect test indications towards non‐FMF hereditary periodic syndromes

Homozygous NLRP7 mutations in a Moroccan woman with recurrent reproductive failure.

International audienc

Identification of a new exon 2-skipped TNFR1 transcript: Regulation by three functional polymorphisms of the TNFR-associated periodic syndrome (TRAPS) gene

Background: Mutations in the TNFRSF1A gene encoding the tumour necrosis factor a cell surface receptor, TNFR1, cause TNFR-associated periodic syndrome (TRAPS) and polymorphisms in TNFRSF1A, including rs4149570, rs767455 and rs1800692, are associated with inflammatory diseases. Objectives: To describe a new exon 2-spliced transcript-TNFR1-d2-and the impact of these three single nucleotide polymorphisms on exon 2 splicing, transcriptional activity of TNFRSF1A and TRAPS phenotype. Methods: Expression of TNFRSF1A transcripts was performed by reverse-transcription-PCR in a range of human cells and tissues. Exon 2 splicing and transcriptional activity were analysed in HEK293T and SW480 cells by in vitro alternative splicing and luciferase assays, respectively. We constructed haplotypes containing rs4149570, rs767455 and rs1800692 in controls (n=72), patients with TRAPS (n=111) and in TRAPS-like patients (n=450) to compare their distribution and association with clinical features of TRAPS. Results: TNFR1-d2 was expressed in a tissue-specific manner, whereas TNFR1 expression was ubiquitous. Alternative splicing assays showed that the T-A-T haplotype at rs4149570-rs767455-rs1800692 had a significantly higher expression of exon 2-skipping product (p=0.02) compared with the G-G-C haplotype. Transcriptional activity from the T-T haplotype at rs4149570-rs1800692 was increased compared with the G-C haplotype (p=0.03). In patients with TRAPS, rs1800692 T/T homozygotes were excessively rare (p<10) and TRAPS-like patients with this genotype experienced less fever. Conclusions: Our study provides a new mechanism of TNFRSF1A regulation whereby three polymorphisms in the promoter, exon 1 and intron 4 have a functional and combined effect on exon 2 splicing, via a coupling mechanism between transcription and splicing. These polymorphisms may affect the phenotype of TRAPS and TRAPS-like patients

NLRP7 in the spectrum of reproductive wastage: Rare non-synonymous variants confer genetic susceptibility to recurrent reproductive wastage

Background: NLRP7 mutations are responsible for recurrent molar pregnancies and associated reproductive wastage. To investigate the role of NLRP7 in sporadic moles and other forms of reproductive wastage, the authors sequenced this gene in a cohort of 135 patients with at least one hydatidiform mole or three spontaneous abortions; 115 of these were new patients. Methods/Results: All mutations were reviewed and their number, nature and locations correlated with the reproductive outcomes of the patients and histopathology of their products of conception. The presence of NLRP7 mutations was demonstrated in two patients with recurrent spontaneous abortions, and some rare non-synonymous variants (NSVs), present in the general population, were found to be associated with recurrent reproductive wastage. These rare NSVs were shown to be associated with lower secretion of interleukin 1β and tumour necrosis factor and therefore to have functional consequences similar to those seen in cells from patients with NLRP7 mutations. The authors also attempted to elucidate the cause of stillbirths observed in 13% of the patients with NLRP7 mutations by examining available placentas of the stillborn babies and live births from patients with mutations or rare NSVs. A number of severe to mild placental abnormalities were found, all of which are known risk factors for perinatal morbidity. Conclusions: The authors recommend close follow-up of patients with NLRP7 mutations and rare NSVs to prevent the death of the rare or reduced number of babies that reach term.link_to_subscribed_fulltex

PSMB10, the last immunoproteasome gene missing for PRAAS

We describe a patient exhibiting clinical features of PRAAS due to a homozygous mutation in PSMB10. This gene encodes the only immunoproteasome subunit in which mutations have not yet been associated with PRAAS

An international external quality assessment for molecular diagnosis of hereditary recurrent fevers: a 3-year scheme demonstrates the need for improvement

Hereditary recurrent fevers (HRF) are rare diseases caused by molecular defects in genes involved in the regulation of innate immunity. Sixty-seven international laboratories participated in an external quality assessment (EQA) scheme, which was developed to appraise the accuracy of genetic testing. Reports were evaluated for the 12 items recommended by the OECD (Organisation for Economic Co-Operation and Development) guidelines for molecular diagnostics. The best documented items were the name of the gene, the biologist, or the patient, whereas information on the test and screening limits, and clinical interpretation of the disease inheritance were scarcely provided. The mutation nomenclature was incomplete in about 70% of the cases. In the first 2 years of EQA, we identified almost 30% genotyping error rate, which decreased markedly in the last year. The combined performance on the basis of the correct identification of all genotypes by a given laboratory in all the 3 years was only 40%, showing a critical need for improvement

Key facts and hot spots on tumor necrosis factor receptor-associated periodic syndrome.

13Tumor necrosis factor receptor-associated periodic syndrome (TRAPS), formerly known as familial Hibernian fever, is the most common autosomal dominant autoinflammatory disease, resulting from mutations in the TNFRSF1A gene, encoding the 55-kD tumor necrosis factor receptor. The pathophysiologic mechanism of TRAPS remains ambiguous and only partially explained. The onset age of the syndrome is variable and the clinical scenery is characterized by recurrent episodes of high-grade fever that typically lasts 1-3 weeks, associated with migrating myalgia, pseudocellulitis, diffuse abdominal pain, appendicitis-like findings, ocular inflammatory signs, and risk of long-term amyloidosis. Fever episodes are responsive to high-dose corticosteroids, but different classes of drugs have been reported to be ineffective. The use of etanercept is unable to control systemic inflammation, while interleukin-1 blockade has been shown as effective in the control of disease activity in many patients reported so far.reservedmixedRigante D; Lopalco G; Vitale A; Lucherini OM; De Clemente C; Caso F; Emmi G; Costa L; Silvestri E; Andreozzi L; Iannone F; Galeazzi M; Cantarini LRigante, D; Lopalco, G; Vitale, A; Lucherini, ORSO MARIA; De Clemente, C; Caso, F; Emmi, G; Costa, L; Silvestri, E; Andreozzi, L; Iannone, F; Galeazzi, Mauro; Cantarini, Luc