Atypical hypergammaglobulinaemia D syndrome with amyloidosis: an overlap with familial Mediterranean fever?

AA amyloidosis revealing mevalonate kinase deficiency: A report of 20 cases including two new French cases and a comprehensive review of literature

INTRODUCTION

Mevalonate kinase deficiency (MKD) is a rare autosomal recessive autoinflammatory disease that can lead to an inflammatory A amyloidosis (AA).

METHODS

To study the occurrence of AA in MKD patients we performed a systemic review of the literature and described two novel patients.

RESULTS

Amyloidosis occurred in 20 MKD patients, renal impairment being always the revealing symptom of AA. Although an accurate prevalence estimation is not possible since exact MKD prevalence is unknown, AA seems rare in MKD (about 6% if we estimate MKD prevalence at 300 patients worldwide). MVK gene study, available in 18 out of the 20 patients, confirmed two pathogenic mutations in all tested individuals. The most frequent genotype was V377I/I268T (n = 9/18). Retrospective search of clinical signs of MKD established, in all patients carrying MVK pathogenic mutations, a disease onset within the first four years of life. Nephrotic syndrome (n = 15), end-stage renal failure (n = 5) or both (n = 8) pointed out kidney amyloidosis. The youngest patient with renal amyloidosis was a European four-year-old girl previously misdiagnosed with PFAPA syndrome. Five patients died of AA amyloidosis despite the use of a biotherapy for two of them; kidney transplant was performed in nine individuals. Colchicine was not effective in any patient. Anti-interleukin-1 anakinra (n = 8), anti TNF etanercept (n = 7) and anti-interleukin 6 tocilizumab (n = 5) treatments were partially effective.

CONCLUSION

Inflammatory A amyloidosis, a rare complication of MKD, can cause death or necessitate kidney transplantation. Early diagnosis and cytokine blocking biotherapy using anti-IL1, anti-TNF or anti-IL6 agents are required to prevent terminal renal failure.

Familial Mediterranean Fever: a review for clinical management

Familial Mediterranean Fever (FMF) is a hereditary autosomal recessive, autoinflammatory disorder characterized by recurrent, self-limiting episodes of short duration (mean 24-72 h) of fever and serositis. FMF is the most frequent periodic febrile syndrome among the autoinflammatory syndromes (AS), a heterogeneous group of recently identified diseases clinically characterized by recurrent febrile attacks, in the absence of autoantibodies and antigen-specific T lymphocytes. In FMF, periodic attacks show inter- and intra-individual variability in terms of frequency and severity. Usually, they are triggered by apparently innocuous stimuli and may be preceded by a prodromal period. The Mediterranean FeVer gene (MEFV) responsible gene maps on chromosome 16 (16p13) encoding the pyrin-marenostrin protein. The precise pathologic mechanism is still to be definitively elucidated; however a new macromolecular complex, called inflammasome, seems to play a major role in the control of inflammation and it might be involved in the pathogenesis of FMF. The most severe long-term complication is type AA amyloidosis, principally affecting the kidney and the cause of chronic renal failure. Two types of risk factors, genetic and non-genetic, have been identified for this complication. Currently, the only effective treatment of Familial Mediterranean Fever is the colchicine. New drugs in a few colchicine resistant patients have been tried, but additional studies on larger series are necessary to draw definitive conclusions.

The systemic autoinflammatory diseases: inborn errors of the innate immune system

The autoinflammatory syndromes are a newly recognized group of immune disorders that lack the high titers of self-reactive antibodies and T cells characteristic of classic autoimmune disease. Nevertheless, patients with these illnesses experience unprovoked inflammatory disease in the absence of underlying infection. Here we discuss recent advances in eight Mendelian autoinflammatory diseases. The causative genes and the proteins they encode play a critical role in the regulation of innate immunity. Both pyrin and cryopyrin, the proteins mutated in familial Mediterranean fever and the cryopyrinopathies, respectively, are involved in regulation of the proinflammatory cytokine, IL-1beta, and may influence the activity of the transcription factor, NFkappaB. NOD2, the Blau syndrome protein, shares certain domains with cryopyrin and appears to be a sensor of intracellular bacteria. PSTPIP1, mutated in the syndrome of pyogenic arthritis with pyoderma gangrenosum and acne, interacts both with pyrin and a protein tyrosine phosphatase to regulate innate and adaptive immune responses. Somewhat unexpectedly, mutations in the p55 TNF receptor lead not to immunodeficiency but to dramatic inflammatory disease, the mechanisms of which are still under investigation. Finally, the discovery of the genetic basis of the hyperimmunoglobulinemia D with periodic fever syndrome has provided a fascinating but incompletely understood link between cholesterol biosynthesis and autoinflammation. In this manuscript, we summarize the current state of the art with regard to the diagnosis, pathogenesis, and treatment of these inborn errors of the innate immune system.

MVK mutations and associated clinical features in Italian patients affected with autoinflammatory disorders and recurrent fever

Autosomal recessive autoinflammatory disorder caused by mutations of the mevalonate kinase gene (MVK), leading to mild, incomplete MK enzyme deficiency (MKD), has been known so far as Hyper-IgD and periodic fever syndrome (HIDS) and regarded as mostly occurring in Northern Europe. Here we report the results of the molecular characterization of the first Italian series of patients affected with autoinflammatory disorders and periodic fever. A total of 13 different mutations, scattered throughout the MVK coding region, were identified in either homozygous or compound heterozygous state in 15 patients. The mutation leading to the V377I amino-acid change, already described also in other series, resulted the most common with a frequency of 50% of all MKD alleles. Among the other mutations, eight had never been described before, including an interstitial deletion of 19 nucleotides in exon 2. In addition to these nucleotide changes, private and polymorphic MVK variants have been detected in the patients under analysis and checked also in a set of control individuals. Clinical features are reported for each of the 15 MKD patients, and life-threatening infections and systemic amyloidosis presented as unexpected MKD-related complications. Our study demonstrates that MKD is a common cause of recurrent fever also in the Italian population, where it is associated with both a wide spectrum of previously unreported MVK mutations and peculiar phenotypic features.

First report of systemic reactive (AA) amyloidosis in a patient with the hyperimmunoglobulinemia D with periodic fever syndrome

Systemic reactive (AA) amyloidosis, leading to renal failure, is a severe complication of most hereditary periodic fever syndromes. The risk of developing this life-threatening condition varies widely among these disorders, being higher for patients affected by familial Mediterranean fever and tumor necrosis factor receptor-associated periodic syndrome. In spite of an acute-phase response during attacks, amyloidosis has never, to date, been described in patients affected with the hyperimmunoglobulinemia D with periodic fever syndrome (HIDS). This is the first report to describe the occurrence of renal AA amyloidosis causing severe nephrotic syndrome in a young Italian man affected with HIDS. The diagnosis of HIDS was established according to clinical, laboratory, and genetic criteria as required by the international Nijmegen HIDS registry. In this patient, 2 mutations in the mevalonate kinase gene were identified, one of which, the leucine-to-arginine substitution at codon 265, is novel.

Progressive bouts of acute abdomen: pet the peritoneum

The recent discovery of the mutated gene responsible for Familial Mediterranean Fever (FMF) is supposed to facilitate its diagnosis which up till now is a clinical one because there are no specific laboratory tests. The sensitivity of genetic testing is limited because these tests search only for known mutations. In this case report we describe a patient with periodic abdominal pain in whom the diagnosis of FMF was wrongly discarded because of lack of a durable effect of colchicine and negative genetic testing. Diffuse peritoneal inflammation was nicely demonstrated by a FDG-PET (fluoro-deoxy-glucose positron-emission tomography) performed during a typical crisis. We discuss the possible diagnostic pitfalls and conclude that a crisis-PET might upgrade the level of diagnostic certainty in equivocal cases.

Familial Mediterranean fever at the millennium. Clinical spectrum, ancient mutations, and a survey of 100 American referrals to the National Institutes of Health

Regarded as the most common and best understood of the hereditary periodic fever syndromes, familial Mediterranean fever (FMF) is a recessively inherited disease of episodic fever with some combination of severe abdominal pain, pleurisy, arthritis, and a characteristic ankle rash. The flares typically last for up to 3 days at a time, and most patients are completely asymptomatic between attacks; if untreated with prophylactic colchicine, some patients later develop amyloidosis and renal failure. The recent cloning of the FMF gene on the short arm of chromosome 16p, and the subsequent finding that its tissue expression is limited to granulocytes, has helped to explain the dramatic accumulation of neutrophils at the symptomatic serosal sites; the wild-type gene likely acts as an upregulator of an anti-inflammatory molecule or as a downregulator of a pro-inflammatory molecule. For nearly half a century, FMF was thought to cluster primarily in non-Ashkenazi Jews, Arabs, Armenians, and Turks, although the screening of the 8 known mutations in an American cohort has identified substantial numbers of people from the Ashkenazi Jewish and Italian populations in the United States who also have this disease. Nevertheless, the symptoms often go unrecognized and patients remain undiagnosed for years, not receiving the highly efficacious colchicine therapy; their histories often include multiple laparotomies, laparoscopies, and psychiatric evaluations. The combinations of clinical manifestations among FMF patients are quite heterogeneous, but our American cohort did not establish any connections between individual mutations and specific clinical pictures--as is seen in other diseases like cystic fibrosis, in which distinct genotypes target certain organ systems. Specifically, the data from our American series are insufficient to evaluate the hypothesis that the M694V/M694V genotype confers a more severe phenotype, or increases the risk of amyloidosis; but both our data and the recent literature (160) indicate that amyloidosis can occur in FMF patients with only 1 copy, or no copies, of the M694V mutation. It appears that specific MEFV mutations are probably not the sole determinants of phenotype, and that unknown environmental factors or modifying genes act as accomplices in this disease. Although we hope the discovery of the FMF gene will allow the diagnosis of FMF to become genetically accurate, the reality is that both clinical and genetic tools must still be used together unless mutations are identified on both of a patient's chromosomes. Physicians should be careful not to rule out the diagnosis in patients of high-risk ethnic backgrounds just because of atypical clinical features, as our data indicate that MEFV mutations are sometimes demonstrable in such patients. At the same time, physicians cannot yet rely solely on a genetic diagnosis because we have not yet identified a sufficient spectrum of mutations, and it is not currently feasible to examine every patient's full DNA sequence for the entire gene; screening an ethnically consistent and clinically positive patient for the 8 known mutations frequently identifies a mutation on only 1 chromosome, and genetic analysis of other classic cases will often reveal none of the 8 mutations. Still, our data suggest that ethnic background is an important predictor of finding 1 of the presently known mutations, and the knowledge of ancestries atypical for FMF can suggest the diagnosis of other hereditary periodic fever syndromes. As the list of FMF-associated MEFV mutations is expanded, and/or new sequencing technologies permit more rapid screening, the value and interpretation of genetic testing for FMF will become more straightforward. Moreover, as the pathophysiology of this disorder becomes less of a hypothesis and more of an understood entity, it is likely that treatment options will broaden beyond the use of daily prophylactic colchicine. (ABSTRACT TRUNCATED)