French practical guidelines for the diagnosis and management of AA amyloidosis.

AA amyloidosis is secondary to the deposit of excess insoluble Serum Amyloid A (SAA) protein fibrils. AA amyloidosis complicates chronic inflammatory diseases, especially chronic inflammatory rheumatisms such as rheumatoid arthritis and spondyloarthritis; chronic infections such as tuberculosis, bronchectasia, chronic inflammatory bowel diseases such as Crohn's disease; and auto-inflammatory diseases including familial Mediterranean fever. This work consists of the French guidelines for the diagnosis workup and treatment of AA amyloidosis. We estimate in France between 500 and 700 cases in the whole French population, affecting both men and women. The most frequent organ impaired is kidney which usually manifests by oedemas of the lower extremities, proteinuria, and/or renal failure. Patients are usually tired and can display digestive features anf thyroid goiter. The diagnosis of AA amyloidosis is based on detection of amyloid deposits on a biopsy using Congo Red staining with a characteristic green birefringence in polarized light. Immunohistochemical analysis with an antibody directed against Serum Amyloid A protein is essential to confirm the diagnosis of AA amyloidosis. Peripheral inflammatory biomarkers can be measured such as C Reactive protein and SAA. We propose an algorithm to guide the etiological diagnosis of AA amyloidosis. The treatement relies on the etiologic treatment of the undelying chronic inflammatory disease to decrease and/or normalize Serum Amyloid A protein concentration in order to stabilize amyloidosis. In case of renal failure, dialysis or even a kidney transplant can be porposed. Nowadays, there is currently no specific treatment for AA amyloidosis deposits which constitutes a therapeutic challenge for the future.

DADA2 diagnosed in adulthood versus childhood: A comparative study on 306 patients including a systematic literature review and 12 French cases.

BACKGROUND: Deficiency of adenosine deaminase 2 (DADA2) is a rare autoinflammatory disease usually presenting before the age of 10 years. Non-specific clinical features or late-onset presentation may delay its diagnosis until adulthood. OBJECTIVE: To determine whether DADA2 diagnosed in adulthood is associated with specific characteristics compared to DADA2 diagnosed in childhood. METHODS: We pooled a cohort of 12 adult DADA2 patients followed in France with cases identified through a systematic literature review. For each patient, we determined the type of clinical presentation and assessed six key organ involvements. RESULTS: A total of 306 cases were included. Among the 283 patients with available data regarding age at diagnosis, 140 were diagnosed during adulthood and 143 during childhood. The vascular presentation of DADA2 was more frequent in the adult diagnosis group (77.9% vs. 62.9%, p < 0.01), whereas the hematological presentation (bone marrow failure) prevailed in the pediatric diagnosis group (10.0% vs. 20.3% p = 0.02). In patients with vasculopathy, severe skin manifestations developed in 35% and 10% of the adult and pediatric diagnosis groups, respectively. Conversely, fewer strokes occurred in the adult group presenting with systemic vasculopathy (54% vs. 81%). Symptomatic humoral immune deficiency (HID) was rarely a clinical presentation in itself (5% and 2.8%) but accompanied other phenotypes of DADA2, especially the hematological phenotype in the adult group (33% vs. 4%). CONCLUSION: DADA2 diagnosed in adulthood presents more often with a vascular phenotype and less often with bone marrow failure than DADA2 diagnosed in childhood. Adults diagnosed with DADA2 vasculopathy display more severe skin involvement but fewer strokes.

LACC1 deficiency links juvenile arthritis with autophagy and metabolism in macrophages.

Juvenile idiopathic arthritis is the most common chronic rheumatic disease in children, and its etiology remains poorly understood. Here, we explored four families with early-onset arthritis carrying homozygous loss-of-expression mutations in LACC1. To understand the link between LACC1 and inflammation, we performed a functional study of LACC1 in human immune cells. We showed that LACC1 was primarily expressed in macrophages upon mTOR signaling. We found that LACC1 deficiency had no obvious impact on inflammasome activation, type I interferon response, or NF-κB regulation. Using bimolecular fluorescence complementation and biochemical assays, we showed that autophagy-inducing proteins, RACK1 and AMPK, interacted with LACC1. Autophagy blockade in macrophages was associated with LACC1 cleavage and degradation. Moreover, LACC1 deficiency reduced autophagy flux in primary macrophages. This was associated with a defect in the accumulation of lipid droplets and mitochondrial respiration, suggesting that LACC1-dependent autophagy fuels macrophage bioenergetics metabolism. Altogether, LACC1 deficiency defines a novel form of genetically inherited juvenile arthritis associated with impaired autophagy in macrophages.

Systemic autoinflammatory diseases: Clinical state of the art.

Systemic autoinflammatory diseases (SAIDs) are defined as disorders of innate immunity. They were initially defined in opposition to autoimmune diseases due to the lack of involvement of the adaptive immune system and circulating autoantibodies. The four historical monogenic diseases are familial Mediterranean fever (associated with MEFV mutations), cryopyrinopathies (NLRP3 mutations), tumor necrosis factor receptor-associated periodic syndrome (TNFRSF1A mutations), and mevalonate kinase deficiency (MVK mutations). In the last 10 years, more than 50 new monogenic SAIDs have been discovered thanks to advances in genetics. Diagnosis is largely based on personal and family history and detailed analysis of signs and symptoms associated with febrile attacks, in the setting of elevated inflammatory markers. Increasingly efficient techniques of genetic analysis can contribute to refining the diagnosis. This review is a guide for the clinician in suspecting and establishing a diagnosis of SAID.

New data in causes of autoinflammatory diseases.

The spectrum of factors known to mediate autoinflammation has broadened recently to include not only interleukin-1 (IL-1) and interferon, but also abnormalities that impair NF-κB pathway negative regulation. The NF-κB pathway is activated upon contact of a ligand with tumor necrosis factor receptor 1 (TNFR1) and plays a pivotal role in triggering the inflammatory process by producing major cytokines such as IL-1, IL-6, and TNF. Negative regulation of the NF-κB pathway, which is essential to stop the inflammatory process, depends on the level of ubiquitination of the proteins associated with TNFR1 and of other intermediate compounds. A20 and otulin are proteins that influence the level of ubiquitination, and a deficiency in either can result in NF-κB activation with overproduction of pro-inflammatory cytokines. Similar to Behçet's disease, A20 haploinsufficiency manifests as oral and genital ulcers and, more rarely, as uveitis. However, transmission is dominant, symptom onset occurs at a younger age, and severe gastrointestinal involvement is at the forefront of the clinical picture. Clinical presentations are extremely diverse. Over their lifetime, affected patients simultaneously or sequentially experience autoinflammatory and autoimmune manifestations. Mild immune deficiency predominantly affecting humoral responses is less common. Otulin deficiency results in systemic inflammatory manifestations at a very young age, with panniculitis, lipodystrophy, and inflammatory bowel disease. The main differential diagnosis is proteasome-associated autoinflammatory syndrome. The treatment of A20 haploinsufficiency and otulin deficiency is challenging and remains unstandardized. The symptoms respond to high-dose glucocorticoid therapy. TNF antagonists and IL-1 antagonists have shown some measure of efficacy.

Mosaicism in autoinflammatory diseases: Cryopyrin-associated periodic syndromes (CAPS) and beyond. A systematic review.

Autoinflammatory diseases (AIDs) are conditions related to defective regulation of the innate immune system. Sanger sequencing of the causative genes has long been the reference for confirming the diagnosis. However, for many patients with a typical AID phenotype, the genetic cause remains unknown. A pioneering study in 2005 demonstrated mosaicism in patients with cryopyrin-associated periodic syndromes (CAPS); the authors found somatic mosaicism in 69% of their cohort of Sanger-negative CAPS patients. We aim to address the extent to which mosaicism contributes to the etiology of AIDs and its impact on phenotype. We retrieved English-language publications reporting mosaicism in AIDs by querying PubMed with no restriction on date and we surveyed French reference centers. We provide a comprehensive clinical and genetic picture of mosaicism in AIDs. We estimate that the proportion of CAPS-like patients presenting mosaicism ranges from 0.5% to 19%. We also discuss the possible links between the proportion of mutated alleles and various clinical features. This review reevaluates the contribution of mosaic DNA variants in CAPS. Mosaicism may be more common than anticipated in other AIDs. No significant difference was demonstrated between variant allele frequency and clinical phenotype. Such knowledge has implications for the development of guidelines for genetic diagnosis, genetic counseling of affected families and effective patient care.

Autosomic dominant familial Behçet disease and haploinsufficiency A20: A review of the literature.

INTRODUCTION: Behçet disease (BD) is a systemic vasculitis involving vessels from any size with various clinical features. Most BD cases are multifactorial and associated with the HLA B51 antigen. In rare and severe early onset cases, dominant Mendelian transmission has been linked to mutations in the TNFAIP3 gene encoding A20. Herein, we propose a systematic review of the literature about the haploinsufficiency A20 (HA20) published cases. SYSTEMATIC REVIEW: Our review of the 45 cases of HA20 from literature highlights the similarities and the differences between this genetic auto-inflammatory disease and classical BD. HA20 looks like BD if we consider recurrent oral (87%) and genital (67%) ulcers, arthralgia or arthritis (42%), skin involvement (53%) such as erythema nodosum or abdominal symptoms (60%) such as abdominal pain, digestive ulcers or diarrhea. However, HA20 differs from classical BD because its geographical distribution is ubiquitous, sex ratio is inversed (one man for two women), first symptoms occur in early childhood (median age = 5.5 years; interquartile range: 1-10) instead of adulthood, recurrent fever is common (62%) unlike classical BD, HLA B51 antigen is uncommon and abdominal symptoms are over-represented compared to classical BD. In addition, response to colchicine in HA20 is inconstant (24%) unlike classical BD. DISCUSSION/CONCLUSION: High fever flares and digestive involvement starting in early childhood seem to be hallmarks of HA20 clinical features. Response to colchicine is unpredictable and biotherapies like anti-TNFα and anti IL1 appear to be treatments of choice, like for other auto-inflammatory diseases. Prospective description of larger cohort of HA20 cases is needed to understand better when this disease must be looked for and how to treat these patients.

A decision tree for the genetic diagnosis of deficiency of adenosine deaminase 2 (DADA2): a French reference centres experience.

Deficiency of adenosine deaminase 2 (DADA2) is a recently described autoinflammatory disorder. Genetic analysis is required to confirm the diagnosis. We aimed to describe the identifying symptoms and genotypes of patients referred to our reference centres and to improve the indications for genetic testing. DNA from 66 patients with clinically suspected DADA2 were sequenced by Sanger or next-generation sequencing. Detailed epidemiological, clinical and biological features were collected by use of a questionnaire and were compared between patients with and without genetic confirmation of DADA2. We identified 13 patients (19.6%) carrying recessively inherited mutations in ADA2 that were predicted to be deleterious. Eight patients were compound heterozygous for mutations. Seven mutations were novel (4 missense variants, 2 predicted to affect mRNA splicing and 1 frameshift). The mean age of the 13 patients with genetic confirmation was 12.7 years at disease onset and 20.8 years at diagnosis. Phenotypic manifestations included fever (85%), vasculitis (85%) and neurological disorders (54%). Features best associated with a confirmatory genotype included fever with neurologic or cutaneous attacks (odds ratio [OR] 10.71, p = 0.003 and OR 10.9, p < 0.001), fever alone (OR 8.1, p = 0.01), and elevated C-reactive protein (CRP) level with neurologic involvement (OR 6.63, p = 0.017). Our proposed decision tree may help improve obtaining genetic confirmation of DADA2 in the context of autoinflammatory symptoms. Prerequisites for quick and low-cost Sanger analysis include one typical cutaneous or neurological sign, one marker of inflammation (fever or elevated CRP level), and recurrent or chronic attacks in adults.

Mutation Update for Kabuki Syndrome Genes KMT2D and KDM6A and Further Delineation of X-Linked Kabuki Syndrome Subtype 2.

Kabuki syndrome (KS) is a rare but recognizable condition that consists of a characteristic face, short stature, various organ malformations, and a variable degree of intellectual disability. Mutations in KMT2D have been identified as the main cause for KS, whereas mutations in KDM6A are a much less frequent cause. Here, we report a mutation screening in a case series of 347 unpublished patients, in which we identified 12 novel KDM6A mutations (KS type 2) and 208 mutations in KMT2D (KS type 1), 132 of them novel. Two of the KDM6A mutations were maternally inherited and nine were shown to be de novo. We give an up-to-date overview of all published mutations for the two KS genes and point out possible mutation hot spots and strategies for molecular genetic testing. We also report the clinical details for 11 patients with KS type 2, summarize the published clinical information, specifically with a focus on the less well-defined X-linked KS type 2, and comment on phenotype-genotype correlations as well as sex-specific phenotypic differences. Finally, we also discuss a possible role of KDM6A in Kabuki-like Turner syndrome and report a mutation screening of KDM6C (UTY) in male KS patients.

The genomic architecture of NLRP7 is Alu rich and predisposes to disease-associated large deletions.

NLRP7 is a major gene responsible for recurrent hydatidiform moles. Here, we report 11 novel NLRP7 protein truncating variants, of which five deletions of more than 1-kb. We analyzed the transcriptional consequences of four variants. We demonstrate that one large homozygous deletion removes NLRP7 transcription start site and results in the complete absence of its transcripts in a patient in good health besides her reproductive problem. This observation strengthens existing data on the requirement of NLRP7 only for female reproduction. We show that two other variants affecting the splice acceptor of exon 6 lead to its in-frame skipping while another variant affecting the splice donor site of exon 9 leads to an in-frame insertion of 54 amino acids. Our characterization of the deletion breakpoints demonstrated that most of the breakpoints occurred within Alu repeats and the deletions were most likely mediated by microhomology events. Our data define a hotspot of Alu instability and deletions in intron 5 with six different breakpoints and rearrangements. Analysis of NLRP7 genomic sequences for repetitive elements demonstrated that Alu repeats represent 48% of its intronic sequences and these repeats seem to have been inserted into the common NLRP2/7 primate ancestor before its duplication into two genes.

Mutation Update for COL2A1 Gene Variants Associated with Type II Collagenopathies.

Mutations in the COL2A1 gene cause a spectrum of rare autosomal-dominant conditions characterized by skeletal dysplasia, short stature, and sensorial defects. An early diagnosis is critical to providing relevant patient care and follow-up, and genetic counseling to affected families. There are no recent exhaustive descriptions of the causal mutations in the literature. Here, we provide a review of COL2A1 mutations extracted from the Leiden Open Variation Database (LOVD) that we updated with data from PubMed and our own patients. Over 700 patients were recorded, harboring 415 different mutations. One-third of the mutations are dominant-negative mutations that affect the glycine residue in the G-X-Y repeats of the alpha 1 chain. These mutations disrupt the collagen triple helix and are common in achondrogenesis type II and hypochondrogenesis. The mutations resulting in a premature stop codon are found in less severe phenotypes such as Stickler syndrome. The p.(Arg275Cys) substitution is found in all patients with COL2A1-associated Czech dysplasia. LOVD-COL2A1 provides support and potential collaborative material for scientific and clinical projects aimed at elucidating phenotype-genotype correlation and differential diagnosis in patients with type II collagenopathies.

Autoinflammation. Management of hereditary recurrent fevers--SHARE experience.

Although new therapeutic options are available for patients with autoinflammatory diseases, evidence-based treatment guidelines are lacking. An initiative in European paediatric rheumatology aims to develop best-practice recommendations for the management of these rare disorders.

Diagnosis of cryopyrin-associated periodic syndrome: challenges, recommendations and emerging concepts.

Cryopyrin-associated periodic syndrome are rare autosomal dominantly inherited diseases. They include three overlapping phenotypes: familial cold autoinflammatory syndrome, Muckle-Wells syndrome, and chronic infantile neurological cutaneous articular syndrome/neonatal onset multisystem autoinflammatory syndrome (NOMID/CINCA). Recurrent fevers, joint pain, and urticarial skin rash are the main clinical features of these conditions. Renal amyloidosis and sensorineural complications may occur. Gain-of-function mutations in NLRP3 gene are responsible for the overactivation of the NLRP3 inflammasome, a multimolecular complex involved in the inflammatory process. Missense mutations are almost always encountered, particularly in exon 3, which encodes the nucleotide-binding domain. Mosaicism is not rare, especially in CINCA/NOMID. Next-generation sequencing will grant access to new insights about NLRP3 implication in oligogenic and multifactorial diseases.