The enlarging clinical, genetic, and population spectrum of tumor necrosis factor receptor–associated periodic syndrome

Objective. To gain insight into the pathophysiology of an unusual autoinflammatory syndrome, in a patient of Armenian origin, that mimicked familial Mediterranean fever (FMF) but with episodes triggered by generalized exposure to cold, and to further elucidate the controversial function of the protein encoded by PYPAF1, whose mutations (exclusively missense to date) have been identified in 3 hereditary recurrent fever syndromes.Methods. The patient's DNA was screened for mutations in both MEFV, the gene responsible for FMF, and PYPAF1. The ability of different recombinant PYPAF1 isoforms, expressed in HEK 293 cells, to regulate NF-B signaling was subsequently assessed.Results. No disease-causing mutation was found in MEFV. However, a nonsense mutation (p.Arg554X) was identified in PYPAF1; this defect resulted in a truncated protein lacking all leucine-rich repeats. Study of the wild-type and mutant PYPAF1 recombinant proteins revealed that PYPAF1 inhibited NF-B proinflammatory pathways, and that the identified nonsense mutation impaired this property.Conclusion. These molecular and clinical findings, together with the clinical manifestations in the patient, which call into question the current nosology of the hereditary recurrent fever syndromes, are consistent with the hypothesis that PYPAF1 acts as an inhibitor of NF-B signaling. They also provide a clear elucidation of the functional consequences of this nonsense PYPAF1 mutation not previously described in the literature, which result in a partial loss of function and may thereby explain the pathophysiology of the autoinflammatory syndrome observed in this patient.

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confidence: 99%

PYPAF1 nonsense mutation in a patient with an unusual autoinflammatory syndrome: Role of PYPAF1 in inflammation

Jéru

Hayrapetyan

Duquesnoy

et al. 2006

“…142680) is a dominantly inherited chronic inflammatory disorder caused by mutations in the extracellular domains of tumor necrosis factor receptor I (TNFRI), the gene for which is TNFRSF1A (1), and characterized by recurrent fevers and abdominal pain. The most common mutations involve cysteine residues, but several variants involving other residues have also been reported (1,2). More than 30 different pathogenic TNFRSF1A mutations have now been identified (see http://fmf.igh.cnrs.fr/infevers/ and ref.…”

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confidence: 99%

Tumor necrosis factor receptor I from patients with tumor necrosis factor receptor–associated periodic syndrome interacts with wild‐type tumor necrosis factor receptor I and induces ligand‐independent NF‐κB activation

Yousaf¹,

Gould²,

Aganna³

et al. 2005

Objective. To investigate the molecular consequences of expressing mutated forms of tumor necrosis factor receptor I (TNFRI) as found in patients with TNFR-associated periodic syndrome (TRAPS).Methods. We cloned and expressed full-length wild-type (WT) and T50K and P46L variants of TNFRI using a new tightly regulated doxycycline-dependent expression system. This system enabled the study of molecular interactions between these receptors at both physiologic and pathophysiologic levels of expression.Results. We used chemical crosslinking on the cell surface to show that WT and mutant forms of TNFRI, derived from TRAPS patients, interact in the absence of TNF ligand. Doxycycline-controlled up-regulation of one TNFRI allele, either WT or mutant, caused downregulation of the other allele, indicating dynamic control of cell surface assembly. We also demonstrated that increased expression of mutant TNFRI (T50K) was associated with a parallel increase in NF-B p65 (RelA) subunit activation, which did not occur with increased expression of WT TNFRI.Conclusion. The T50K TRAPS-related variant is capable of sustaining inappropriate NF-B activation, resulting in persistent autoinflammation in target organs such as skin, synovial membrane, and the central nervous system. We conclude that some of the inflammatory processes seen in TRAPS do not involve direct interaction of TNF with its receptors, but that other proinflammatory mechanisms capable of up-regulating TNFRI expression may cause cellular activation through the NF-B signaling pathway.Tumor necrosis factor receptor-associated periodic syndrome (TRAPS; MIM no. 142680) is a dominantly inherited chronic inflammatory disorder caused by mutations in the extracellular domains of tumor necrosis factor receptor I (TNFRI), the gene for which is TNFRSF1A (1), and characterized by recurrent fevers and abdominal pain. The most common mutations involve cysteine residues, but several variants involving other residues have also been reported (1,2). More than 30 different pathogenic TNFRSF1A mutations have now been identified (see http://fmf.igh.cnrs.fr/infevers/ and ref.2), mostly located in either the first or second cysteine-rich N-terminal extracellular domain (CRD1 or CRD2) of TNFRSF1A (2,3). Impaired cleavage of the TNFRI (p55) ectodomain upon cellular activation has been demonstrated as a pathogenic mechanism in some but not all TNFRI variants (3-6) and did not relate to the severity of the phenotype (7,8).Biologic activities of TNF are mediated through 2 TNFRs, TNFRI and TNFRII (TNFR superfamily 1B

“…The patient's father was a healthy V377I heterozygote and showed a slightly depressed MK enzyme activity, while her mother 1956 STOJANOV ET AL was an asymptomatic carrier of the TNFRSF1A R92Q substitution. Generally, R92Q is regarded as a low-penetrance mutation associated with a broader range of symptoms than most TRAPS mutations and found especially in sporadic cases of TRAPS (12), although segregation with disease has been observed in 4 families (23). The R92Q allele frequency ranges from 1.8% (23) to 3.3% (12) in patients with clinical symptoms suggestive of TRAPS and amounts to ϳ1% in Irish and North American control populations (12).…”

Section: Discussionmentioning

confidence: 99%

Molecular analysis of the MVK and TNFRSF1A genes in patients with a clinical presentation typical of the hyperimmunoglobulinemia D with periodic fever syndrome: A low‐penetrance TNFRSF1A variant in a heterozygous MVK carrier possibly influences the phenotype of hyperimmunoglobulinemia D with periodic fever syndrome or vice versa

Stojanov¹,

Lohse²,

Lohse³

et al. 2004

Objective. To describe biochemical findings and the spectrum of mevalonate kinase (MVK) gene mutations as well as an associated TNFRSF1A lowpenetrance variant in a series of patients with clinical features of the hyperimmunoglobulinemia D with periodic fever syndrome (HIDS).Methods. The MVK gene was sequenced in 8 children and 1 adult (including 2 siblings) fulfilling the clinical criteria for HIDS. In addition, sequencing of exons 2, 3, 4, and 6 of the TNFRSF1A gene was performed in patients with only one or no MVK mutation. Mevalonate kinase (MK) enzyme activity in leukocytes and renal excretion of mevalonic acid were also measured.Results. Mutations in the coding region of the MVK gene were detected in 6 patients, and the most common mutation was V377I. Among these patients were 2 novel mutations, both of which were located in exon 6. These novel mutations resulted in the substitution of tryptophan (TGG) by a stop codon (TGA) at amino acid position 188 (W188X) and in the exchange of valine (GTG) for alanine (GCG) at amino acid position 203 (V203A). In 1 patient, a combination of one MVK (V377I) mutation and one TNFRSF1A (R92Q) mutation was present. The patient's clinical phenotype resembled a mixture of variant-type HIDS and tumor necrosis factor receptor-associated periodic syndrome (TRAPS). Her IgD values varied between normal and slightly increased, and the MK activity was in the low-normal range, while urinary mevalonate concentrations were always normal.Conclusion. The genotype findings indicate that a relatively small number of genes may be involved in the clinical manifestation of HIDS, with low-penetrance TNFRSF1A variants possibly influencing the HIDS phenotype or MVK mutations contributing to TRAPS.The hyperimmunoglobulinemia D with periodic fever syndrome (HIDS; MIM no. 260920) is an autosomal recessively inherited autoinflammatory disease. It is characterized by febrile episodes of 3-7 days' duration recurring every 4-8 weeks and by a persistently high serum level of IgD (Ͼ100 IU/ml). Symptoms accompanying a typical attack comprise cervical lymphadeno-