Search

Objective: To identify the molecular basis of a systemic autoinflammatory disorder (SAID) evocative of TNF receptor-associated periodic syndrome (TRAPS)., Methods: (i) Deep next generation sequencing (NGS) through a SAID gene panel; (ii) variant allele distribution in peripheral blood subpopulations; (iii) in silico analyses of mosaic variants using TNF receptor superfamily 1A (TNFRSF1A) crystal structure; (iv) review of the very rare TNFRSF1A mosaic variants reported previously., Results: In a 36-year-old man suffering from recurrent fever for 12 years, high-depth NGS revealed a TNFRSF1A mosaic variant, c.176G>A p.(Cys59Tyr), which Sanger sequencing failed to detect. This mosaic variant displayed a variant allele fraction of 14% in whole blood; it affects both myeloid and lymphoid lineages. p.(Cys59Tyr), a recurrent germline pathogenic variant, affects a crucial cysteine located in the first cysteine-rich domain (CRD1) and involved in a disulphide bridge. Introduction of a tyrosine at this position is expected to disrupt the CRD1 structure. Review of the three previously reported TNFRSF1A mosaic variants revealed that they are all located in a small region of CRD2 and that germinal cells can be affected., Conclusion: This study expands the localization of TNFRSF1A mosaic variants to the CRD1 domain. Noticeably, residues involved in germline TNFRSF1A mutational hot spots can also be involved in post-zygotic mutational events. Including our study, only four patients have been thus far reported with TNFRSF1A mosaicism, highlighting the need for a high-depth NGS-based approach to avoid the misdiagnosis of TRAPS. Genetic counselling has to consider the potential occurrence of TNFRSF1A mosaic variants in germinal cells., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: Cryopyrin-associated periodic syndrome (CAPS) is a rare but treatable inherited autoinflammatory condition including familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS) and chronic infantile neurologic cutaneous articular syndrome (CINCA). Our objective was to describe the main features of CAPS AA amyloidosis (AA-CAPS) associated and the efficacy of IL-1 inhibitors in this indication., Methods: Retrospective study in France associated with a systematic literature review., Results: Eighty-six patients were identified: 23 new French cases and 63 from the literature, with a median age at amyloidosis diagnosis of 39 years old. CAPS subtypes were MWS (n = 62), FCAS (n = 9), frontier forms between MWS and FCAS (n = 12) and between CINCA and MWS (n = 3). NLRP3 had been sequenced in 60 patients (70%) and the most frequent mutation was R260W (60%). Three AA-CAPS patients displayed somatic NLRP3 mutations. Death occurred in 35 patients (41%), none of whom having ever received IL-1 inhibitors. Twenty-eight patients (33%) received IL-1 inhibitors, with a >50% decrease in proteinuria in 89% of cases., Conclusion: AA amyloidosis can occur in nearly all CAPS subtypes. IL-1 inhibitors are effective, underlining the necessity of an early diagnosis of CAPS in order to start this treatment as soon as possible among AA-CAPS patients., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objectives: TNF receptor-1-associated periodic syndrome (TRAPS) is a rare autosomal dominant autoinflammatory disorder associated with mutations in the TNF receptor super family 1 A (TNFRSF1A) gene. AA amyloidosis (AA) is the most severe complication of TRAPS. To study the occurrence and prognosis of AA in TRAPS, we conducted a retrospective study of all French cases and a systematic literature review., Methods: This case series includes TRAPS patients followed by our centre from 2000 to 2020 presenting with histologically confirmed AA. We conducted a systematic literature review on the PubMed and EMBASE databases for articles published up to February 2021 following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines and using the keywords: amyloidoisis, amyloid, TNF receptor-associated periodic syndrome, TNF receptor-associated periodic syndrome, tumor necrosis factor receptor-associated periodic syndrome, TRAPS, TNFRSF1A, familial hibernian fever and hibernian familial fever., Results: A total of 41 TRAPS with AA were studied: three new patients and 38 cases from the literature. AA diagnosis preceded that of TRAPS in 96% of cases, and 17/36 (47%) required renal replacement therapy. Death occurred in 5/36 (14%) with a median follow-up of 23 months. Effect of biologics on AA were available for 21 regimens in 19 patients: 10 improved renal function, seven stabilized and four worsened. Four patients (36% of transplanted patients) relapse AA on kidney graft (only one under etanercept)., Conclusion: TRAPS is revealed by AA in most cases. Therefore, clinical features of TRAPS should be screened for in AA patients. IL-1 antagonist can help to normalize inflammation and to preserve renal function., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Congenital hyperinsulinism (CHI) is associated with focal hyperplasia of endocrine tissue in 40-65% of patients. Focal CHI is sporadic and is caused by a germline, paternally inherited, mutation of the SUR1 (ABCC8) or KIR6.2 (KCNJ11) genes (encoding subunits of the pancreatic ATP-dependent potassium channel) together with somatic maternal haploinsufficiency for 11p15.5. Plurifocal or large forms of focal CHI are a cause of apparent failure of surgery, and their underlying mechanism has not been thoroughly investigated., Patients: We here report two patients with bifocal CHI as evidenced by relapsing hypoglycemia after removal of the first focal lesion and the detection of a second, distinct, focal adenomatous hyperplasia during later surgery (patients 1 and 2) and a patient with a giant focal lesion involving the major part of the pancreas (patient 3)., Results: In the three patients, a germline, paternally inherited, mutation of SUR1 was found. In patients 1 and 2, haploinsufficiency for the maternal 11p15.5 region resulted from a somatic deletion specific for each of the focal lesions, as shown by the diversity of deletion break points. In patient 3, an identical somatic maternal 11p15 deletion demonstrated by similar break points was shown in two independent lesion samples, suggesting a very early event during pancreas embryogenesis., Conclusion: Individual patients with focal hyperinsulinism may have more than one focal pancreatic lesion due to separate somatic maternal deletion of the 11p15 region. These patients and those with solitary focal lesions may follow the two-hit model described by Knudson. The stage of embryogenesis at which the somatic event occurs may account for the observed histological diversity (early event giant lesion, later event small lesion).

Context: Congenital hyperinsulinism (HI) is characterized by hypoglycemia related to inappropriate insulin secretion. Focal and diffuse forms of hyperinsulinism share a similar clinical presentation, but their treatment is dramatically different. Preoperative differential diagnosis was based on pancreatic venous sampling, a technically demanding technique., Objective: Positron emission tomography (PET) after injection of [18F]fluoro-L-DOPA (L-dihydroxyphenylalanine) has been evaluated for the preoperative differentiation between focal and diffuse HI, by imaging uptake of radiotracer and the conversion of [18F]fluoro-L-dopa into dopamine by DOPA decarboxylase. We propose to validate this test by immunohistochemical approach., Patients and Methods: Pancreatic surgical specimens of four focal and three diffuse HI were studied, using anti-DOPA decarboxylase and proinsulin antibodies. The effect of an inhibitor of DOPA decarboxylase (carbidopa) on insulin secretion was evaluated in vivo and in cultured INS-1 cells., Results: Immunohistochemical detection of DOPA decarboxylase showed diffuse staining of Langerhans islets in the whole pancreas in all diffuse cases, in contrast with dense focal staining in all focal cases. Staining of Langerhans islets outside the focal lesion was diffusely but weakly positive. We correlated the localization of DOPA decarboxylase and proinsulin in normal pancreas and in both diffuse and focal HI tissues. The diffuse PET uptake found before treatment in one child with diffuse HI disappeared completely after carbidopa administration, suggesting in vivo that pancreatic cells can take up amine precursors and contain DOPA decarboxylase. The insulin secretion measured in the supernatant was the same whether INS-1 cells were treated by dopamine or Lodosyn or untreated., Conclusion: We validate PET with as a consistent test to differentiate diffuse and focal HI.

Context: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disorder caused by mutations in the gene AIRE (autoimmune regulator). APECED affects mainly endocrine organs resulting in hypoparathyroidism, adrenocortical failure, diabetes mellitus, hypogonadism, and hypothyroidism. Nonendocrine organ manifestations are autoimmune hepatitis, vitiligo, pernicious anemia, exocrine pancreatic insufficiency, and alopecia. APECED's first manifestation generally is mucocutaneous candidiasis presumably related to T cell dysfunction., Patient: A 5-yr-old Iranian girl presented first with pernicious anemia, exocrine pancreatic insufficiency, and nail candidiasis. She had renal dysfunction due to chronic interstitial nephritis (CIN), which progressed to end-stage renal failure. She was transplanted 1 yr later. Common causes of CIN were excluded. APECED was suspected first because she developed progressively hypoparathyroidism, adrenocortical failure, glucose intolerance, and hypothyroidism., Results: Genetic analysis revealed a large homozygous deletion (g.424_2157del1734), spanning exons 2-4, in the AIRE gene. The predicted protein, if it is produced, has only 44 amino acids (exon 1) in common with the wild-type protein. Immunosuppression after the first renal transplant included prednisone, azathioprine, and cyclosporine A. Multiple acute rejection episodes occurred. Chronic rejection resulted in lost graft and she was retransplanted 2 yr later. Surprisingly, all APECED-related symptoms including candidiasis and autoantibody levels decreased, presumably due to the reinforced immunosuppression (tacrolimus, mycophenolate mofetil, prednisone)., Conclusions: This is the first report of an APECED patient with CIN resulting in end-stage renal failure. Clinical and biological improvement was observed under posttransplant multidrug immunosuppression including tacrolimus and mycophenolate mofetil.

Hypoglycemia occasionally results from oxidative phosphorylation deficiency, associated with liver failure. Conversely, in some cases of respiratory chain defect, the impairment in glucose metabolism occurs with normal hepatic function. The mechanism for this hypoglycemia remains poorly understood. We report here three unrelated children with hypoglycemia as the presenting symptom associated with oxidative phosphorylation deficiency but without liver dysfunction. Two patients had, respectively, complex III and complex IV deficiency and presented with long fast hypoglycemia. During a fasting test, the first patient showed evidence for impaired gluconeogenesis (progressive increase of plasma lactate and no decrease of alanine levels), whereas the second patient appeared to have impaired fatty acid oxidation (hypoketotic hypoglycemia with increased levels of non esterified fatty acids). The third patient presented with both long and short fast hypoglycemia related to complex IV deficiency. The mechanism of hypoglycemia for this patient may have been partly related to GH insufficiency, whereas impaired glycogen metabolism possibly accounted for short fast hypoglycemia. We suggest that hypoglycemia can be the presenting symptom for respiratory chain defects, through the possible reduction in cofactors resulting from oxidative phosphorylation deficiency, and that respiratory chain defects should therefore be considered in the differential diagnosis of hypoglycemia.

Congenital hyperinsulinism (CHI) is related to two main histological pancreas anomalies: focal adenomatous hyperplasia and diffuse beta-cell hypersecretion. Pharmacological tests to measure acute insulin responses (AIR) to peripheral i.v. injections of glucose, calcium, and tolbutamide have been reported as potential means to distinguish between these histological forms. In patients with defects in ATP-sensitive potassium channels, tolbutamide will fail to induce insulin release in affected portions of the pancreas, whereas calcium gluconate will enhance insulin release through spontaneously active voltage-gated Ca(2+) channels. Consequently, in focal CHI patients, calcium should promote AIRs from the lesion, whereas tolbutamide should act to promote insulin secretion from the healthy region of the pancreas (outside the focal hyperplasia). We therefore studied AIRs to calcium and tolbutamide stimulation tests in 16 children with focal (n = 9) or diffuse (n = 7) CHI before pancreatic surgery. We found hypervariable AIRs to glucose and calcium stimulation in both focal and diffuse CHI patients. AIRs to tolbutamide stimulation were found modest in focal CHI patients, which might account for beta-cell quiescence in the healthy portion of the pancreas of these patients. We conclude that AIRs to calcium and tolbutamide stimulation tests are not sufficient to differentiate the focal from the diffuse CHI patients.