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American Journal of Medical Genetics.... Jul 2022Hereditary sensory and autonomic neuropathy type 2B (HSAN2B) is a rare autosomal recessive peripheral neuropathy caused by biallelic variants in RETREG1...
Hereditary sensory and autonomic neuropathy type 2B (HSAN2B) is a rare autosomal recessive peripheral neuropathy caused by biallelic variants in RETREG1 (formerly FAM134B). HSAN2B is characterized by sensory impairment resulting in skin ulcerations, amputations, and osteomyelitis as well as variable weakness, spasticity, and autonomic dysfunction. Here, we report four affected individuals with recurrent osteomyelitis, ulceration, and amputation of hands and feet, sensory neuropathy, hyperhidrosis, urinary incontinence, and renal failure from a family without any known shared parental ancestry. Due to the history of chronic recurrent multifocal osteomyelitis and microcytic anemia, a diagnosis of Majeed syndrome was considered; however, sequencing of LPIN2 was negative. Family-based exome sequencing (ES) revealed a novel homozygous ultrarare RETREG1 variant NM_001034850.2:c.321G>A;p.Trp107Ter. Electrophysiological studies of the proband demonstrated axonal sensorimotor neuropathy predominantly in the lower extremities. Consistent with the lack of shared ancestry, the coefficient of inbreeding calculated from ES data was low (F = 0.002), but absence of heterozygosity (AOH) analysis demonstrated a 7.2 Mb AOH block surrounding the variant consistent with a founder allele. Two of the four affected individuals had unexplained renal failure which has not been reported in HSAN2B cases to date. Therefore, this report describes a novel RETREG1 founder allele and suggests renal failure may be an unrecognized feature of the RETREG1-disease spectrum.
Topics: Alleles; Hereditary Sensory and Autonomic Neuropathies; Humans; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Osteomyelitis; Pedigree; Renal Insufficiency
PubMed: 35332675
DOI: 10.1002/ajmg.a.62727 -
Iranian Journal of Pediatrics Jun 2014Periodic fever syndromes are a group of diseases characterized by episodes of fever with healthy intervals between febrile episodes. In the first part of this paper, we...
Periodic fever syndromes are a group of diseases characterized by episodes of fever with healthy intervals between febrile episodes. In the first part of this paper, we presented a guideline for approaching patients with periodic fever and reviewed two common disorders with periodic fever in Iranian patients including familial Mediterranean fever (FMF) and periodic fever syndromes except for periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA). In this part, we review other autoinflammatory disorders including hyper IgD, tumor necrosis factor receptor-associated periodic syndrome (TRAPS), cryopyrin associated periodic syndromes, autoinflammatory bone disorders and some other rare autoinflammatory disorders such as Sweet's and Blau syndromes. In cryopyrin associated periodic syndromes group, we discussed chronic infantile neurologic cutaneous and articular (CINCA) syndrome, Muckle-Wells syndrome and familial cold autoinflammatory syndrome. Autoinflammatory bone disorders are categorized to monogenic disorders such as pyogenic arthritis, pyoderma ;gangraenosum and acne (PAPA) syndrome, the deficiency of interleukine-1 receptor antagonist (DIRA) and Majeed syndrome and polygenic background or sporadic group such as chronic recurrent multifocal osteomyelitis (CRMO) or synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome are classified in sporadic group. Other autoinflammatory syndromes are rare causes of periodic fever in Iranian system registry.
PubMed: 25562014
DOI: No ID Found -
Mediators of Inflammation 2013Treatment of monogenic autoinflammatory disorders, an expanding group of hereditary diseases characterized by apparently unprovoked recurrent episodes of inflammation,... (Review)
Review
Treatment of monogenic autoinflammatory disorders, an expanding group of hereditary diseases characterized by apparently unprovoked recurrent episodes of inflammation, without high-titre autoantibodies or antigen-specific T cells, has been revolutionized by the discovery that several of these conditions are caused by mutations in proteins involved in the mechanisms of innate immune response, including components of the inflammasome, cytokine receptors, receptor antagonists, and oversecretion of a network of proinflammatory molecules. Aim of this review is to synthesize the current experience and the most recent evidences about the therapeutic approach with biologic drugs in pediatric and adult patients with monogenic autoinflammatory disorders.
Topics: Acne Vulgaris; Anemia, Dyserythropoietic, Congenital; Arthritis; Arthritis, Infectious; Biological Products; Cranial Nerve Diseases; Cryopyrin-Associated Periodic Syndromes; Familial Mediterranean Fever; Fever; Hereditary Autoinflammatory Diseases; Humans; Immunity, Innate; Immunologic Deficiency Syndromes; Inflammation; Intracellular Signaling Peptides and Proteins; Mevalonate Kinase Deficiency; Mutation; Osteomyelitis; Pyoderma Gangrenosum; Receptors, Interleukin-1; Sarcoidosis; Synovitis; T-Lymphocytes; Treatment Outcome; Uveitis
PubMed: 23970817
DOI: 10.1155/2013/939847 -
International Journal of Molecular... Mar 2021Lipin2 is a phosphatidate phosphatase that plays critical roles in fat homeostasis. Alterations in , which encodes lipin2, cause the autoinflammatory bone disorder...
Lipin2 is a phosphatidate phosphatase that plays critical roles in fat homeostasis. Alterations in , which encodes lipin2, cause the autoinflammatory bone disorder Majeed syndrome. Lipin2 limits lipopolysaccharide (LPS)-induced inflammatory responses in macrophages. However, little is known about the precise molecular mechanisms underlying its anti-inflammatory function. In this study, we attempted to elucidate the molecular link between the loss of lipin2 function and autoinflammatory bone disorder. Using a knockout murine macrophage cell line, we showed that lipin2 deficiency enhances innate immune responses to LPS stimulation through excessive activation of the NF-κB signaling pathway, partly because of TAK1 signaling upregulation. Lipin2 depletion also enhanced RANKL-mediated osteoclastogenesis and osteoclastic resorption activity accompanied by NFATc1 dephosphorylation and increased nuclear accumulation. These results suggest that lipin2 suppresses the development of autoinflammatory bone disorder by fine-tuning proinflammatory responses and osteoclastogenesis in macrophages. Therefore, this study provides insights into the molecular pathogenesis of monogenic autoinflammatory bone disorders and presents a potential therapeutic intervention.
Topics: Adipose Tissue; Anemia, Dyserythropoietic, Congenital; Animals; Bone Resorption; Cell Differentiation; Humans; Immunologic Deficiency Syndromes; Inflammation; Lipopolysaccharides; MAP Kinase Kinase Kinases; Macrophages; Mice; Mice, Knockout; NF-kappa B; NFATC Transcription Factors; Nuclear Proteins; Osteoclasts; Osteogenesis; Osteomyelitis; RANK Ligand; Signal Transduction; Transcription Factor RelA
PubMed: 33809261
DOI: 10.3390/ijms22062893 -
Proceedings of the National Academy of... Sep 2012The three lipin phosphatidate phosphatase (PAP) enzymes catalyze a step in glycerolipid biosynthesis, the conversion of phosphatidate to diacylglycerol. Lipin-1 is...
The three lipin phosphatidate phosphatase (PAP) enzymes catalyze a step in glycerolipid biosynthesis, the conversion of phosphatidate to diacylglycerol. Lipin-1 is critical for lipid synthesis and homeostasis in adipose tissue, liver, muscle, and peripheral nerves. Little is known about the physiological role of lipin-2, the predominant lipin protein present in liver and the deficient gene product in the rare disorder Majeed syndrome. By using lipin-2-deficient mice, we uncovered a functional relationship between lipin-1 and lipin-2 that operates in a tissue-specific and age-dependent manner. In liver, lipin-2 deficiency led to a compensatory increase in hepatic lipin-1 protein and elevated PAP activity, which maintained lipid homeostasis under basal conditions, but led to diet-induced hepatic triglyceride accumulation. As lipin-2-deficient mice aged, they developed ataxia and impaired balance. This was associated with the combination of lipin-2 deficiency and an age-dependent reduction in cerebellar lipin-1 levels, resulting in altered cerebellar phospholipid composition. Similar to patients with Majeed syndrome, lipin-2-deficient mice developed anemia, but did not show evidence of osteomyelitis, suggesting that additional environmental or genetic components contribute to the bone abnormalities observed in patients. Combined lipin-1 and lipin-2 deficiency caused embryonic lethality. Our results reveal functional interactions between members of the lipin family in vivo, and a unique role for lipin-2 in central nervous system biology that may be particularly important with advancing age. Additionally, as has been observed in mice and humans with lipin-1 deficiency, the pathophysiology in lipin-2 deficiency is associated with dysregulation of lipid intermediates.
Topics: Aging; Analysis of Variance; Animals; Blood Cell Count; Blotting, Western; Bone and Bones; Cerebellum; DNA Primers; Galactosides; Gene Expression Profiling; Histological Techniques; Homeostasis; Immunohistochemistry; Indoles; Liver; Locomotion; Mice; Mice, Transgenic; Nuclear Proteins; Phosphatidate Phosphatase; Phospholipids; Polymerase Chain Reaction; Psychomotor Performance; Radiography; Reflex, Startle
PubMed: 22908270
DOI: 10.1073/pnas.1205221109 -
The Journal of Biological Chemistry Oct 2009Mammalian lipins (lipin-1, lipin-2, and lipin-3) are Mg2+-dependent phosphatidate phosphatase (PAP) enzymes, which catalyze a key reaction in glycerolipid biosynthesis....
Mammalian lipins (lipin-1, lipin-2, and lipin-3) are Mg2+-dependent phosphatidate phosphatase (PAP) enzymes, which catalyze a key reaction in glycerolipid biosynthesis. Lipin-1 also functions as a transcriptional coactivator in conjunction with members of the peroxisome proliferator-activated receptor family. An S734L mutation in LPIN2 causes Majeed syndrome, a human inflammatory disorder characterized by recurrent osteomyelitis, fever, dyserythropoietic anemia, and cutaneous inflammation. Here we demonstrate that mutation of the equivalent serine in mouse lipin-1 and lipin-2 to leucine or aspartate abolishes PAP activity but does not impair lipin association with microsomal membranes, the major site of glycerolipid synthesis. We also determined that lipin-2 has transcriptional coactivator activity for peroxisome proliferator-activated receptor-response elements similar to lipin-1 and that this activity is not affected by mutating the conserved serine. Therefore, our results indicate that the symptoms of the Majeed syndrome result from a loss of lipin-2 PAP activity. To characterize sites of lipin-2 action, we detected lipin-2 expression by in situ hybridization on whole mouse sections and by quantitative PCR of tissues relevant to Majeed syndrome. Lipin-2 was most prominently expressed in liver, where levels were much higher than lipin-1, and also in kidney, lung, gastrointestinal tract, and specific regions of the brain. Lipin-2 was also expressed in circulating red blood cells and sites of lymphopoiesis (bone marrow, thymus, and spleen). These results raise the possibility that the loss of lipin-2 PAP activity in erythrocytes and lymphocytes may contribute to the anemia and inflammation phenotypes observed in Majeed syndrome patients.
Topics: Amino Acid Substitution; Anemia, Dyserythropoietic, Congenital; Animals; Cell Line; Dermatitis; Fever; Gene Expression Regulation, Enzymologic; Humans; Mice; Mutation, Missense; Nuclear Proteins; Organ Specificity; Osteomyelitis; Peroxisome Proliferator-Activated Receptors; Phosphatidate Phosphatase; Response Elements; Serine; Syndrome
PubMed: 19717560
DOI: 10.1074/jbc.M109.023663 -
Iranian Journal of Pediatrics Oct 2014
PubMed: 25793079
DOI: No ID Found -
The Journal of Biological Chemistry Jun 2014Lipin 2 is a phosphatidic acid phosphatase (PAP) responsible for the penultimate step of triglyceride synthesis and dephosphorylation of phosphatidic acid (PA) to...
Lipin 2 is a phosphatidic acid phosphatase (PAP) responsible for the penultimate step of triglyceride synthesis and dephosphorylation of phosphatidic acid (PA) to generate diacylglycerol. The lipin family of PA phosphatases is composed of lipins 1-3, which are members of the conserved haloacid dehalogenase superfamily. Although genetic alteration of LPIN2 in humans is known to cause Majeed syndrome, little is known about the biochemical regulation of its PAP activity. Here, in an attempt to gain a better general understanding of the biochemical nature of lipin 2, we have performed kinetic and phosphorylation analyses. We provide evidence that lipin 2, like lipin 1, binds PA via the electrostatic hydrogen bond switch mechanism but has a lower rate of catalysis. Like lipin 1, lipin 2 is highly phosphorylated, and we identified 15 phosphosites. However, unlike lipin 1, the phosphorylation of lipin 2 is not induced by insulin signaling nor is it sensitive to inhibition of the mammalian target of rapamycin. Importantly, phosphorylation of lipin 2 does not negatively regulate either membrane binding or PAP activity. This suggests that lipin 2 functions as a constitutively active PA phosphatase in stark contrast to the high degree of phosphorylation-mediated regulation of lipin 1. This knowledge of lipin 2 regulation is important for a deeper understanding of how the lipin family functions with respect to lipid synthesis and, more generally, as an example of how the membrane environment around PA can influence its effector proteins.
Topics: Amino Acid Motifs; Animals; Humans; Hydrogen Bonding; Insulin; Kinetics; Mice; Phosphatidate Phosphatase; Phosphatidic Acids; Phosphorylation; Protein Binding; Signal Transduction; Static Electricity
PubMed: 24811178
DOI: 10.1074/jbc.M114.547604 -
Frontiers in Pediatrics 2023Non-bacterial osteomyelitis (NBO) is a rare chronic inflammatory bone disease related to immune system dysregulation. This disease belongs to a family of...
Juvenile idiopathic arthritis with systemic onset with inflammatory bone lesions: two case reports of patients successfully treated with canakinumab and experience gained from literature.
UNLABELLED
Non-bacterial osteomyelitis (NBO) is a rare chronic inflammatory bone disease related to immune system dysregulation. This disease belongs to a family of autoinflammatory diseases. It often coexists with other TNF-α-mediated immune-mediated diseases such as juvenile idiopathic arthritis (JIA) and inflammatory bowel diseases. Previously, interleukin-1-driven inflammation was described predominantly in monogenic cases of NBO, such as DIRA syndrome or Majeed syndrome. However, the association between NBO and JIA with systemic onset (soJIA) has not been described yet. Herein, we describe the cases of two patients with soJIA with inflammatory bone lesions wherein canakinumab (anti-interleukin-1β antibodies) caused remission.
CASE DESCRIPTIONS
Patient 1-A 6-month-old boy with typical soJIA suffered a destruction of the 7th to 9th ribs and the left pubic bone. Antibiotics, IVIG, and cyclosporine proved ineffective. Corticosteroids were effective, but due to the factor of corticosteroid dependence, which has some disadvantages, canakinumab with a dosage of 4 mg/kg was initiated every 4 weeks, which completely controlled the disease and allowed to taper corticosteroids.Patient 2-A 2-year-old girl developed chronic non-bacterial osteomyelitis of the 5th rib 2 months after taking corticosteroids prescribed for typical soJIA. She underwent surgical debridement removal, and several courses of antibiotics proved ineffective. She developed macrophage activation syndrome, following which anakinra was prescribed, which resulted in only temporary improvement. Therefore, this drug was switched to canakinumab, which caused corticosteroid-free remission.
CONCLUSION
This is the first description of a rare association of soJIA with inflammatory bone lesions with the proven efficacy of IL-1 blockade. The association of two autoinflammatory conditions should indicate IL-1-driven mechanisms and a possible genetic basis. Follow-up genetic and functional studies are required to better understand the pathogenesis of such overlapping diseases.
PubMed: 37325364
DOI: 10.3389/fped.2023.1163483 -
Arthritis and Rheumatism Dec 2011Monogenic autoinflammatory diseases are disorders of Mendelian inheritance that are characterized by mutations in genes that regulate innate immunity and whose typical...
OBJECTIVE
Monogenic autoinflammatory diseases are disorders of Mendelian inheritance that are characterized by mutations in genes that regulate innate immunity and whose typical features are systemic inflammation without high-titer autoantibodies or antigen-specific T cells. Skin and bone inflammation in the newborn period have been described in 3 of these autoinflammatory disorders: neonatal-onset multisystem inflammatory disease, Majeed syndrome, and deficiency of interleukin-1 (IL-1) receptor antagonist (DIRA) syndrome. This study was undertaken to present the characteristics of the DIRA syndrome in 2 cases from Brazil, and describe a novel mutation in IL1RN.
METHODS
Two unrelated Brazilian patients were evaluated for the clinical signs and symptoms of these 3 disorders, and peripheral blood samples were assessed for mutations in NLRP3, LPIN2, and IL1RN by DNA resequencing analysis. A mutation in IL1RN that encodes a mutant protein was identified, and the expression and function of this mutant protein were compared to those of the wild-type protein.
RESULTS
Both patients presented with pustular dermatitis resembling generalized pustular psoriasis, recurrent multifocal aseptic osteomyelitis, and elevation in the levels of acute-phase reactants, all of which are features most consistent with the DIRA syndrome. Chronic lung disease was observed in 1 of the patients, and jugular venous thrombosis was observed in the other patient. Both patients showed a partial response to corticosteroid therapy, and 1 patient experienced an initial improvement of dermatitis with the use of acitretin. Both patients were homozygous for a novel 15-bp (in-frame) deletion on the IL1RN gene. The mutated protein expressed in vitro had no affinity with the IL-1 receptor, and stimulation of the patients' cells with recombinant human IL-1α or IL-1β led to oversecretion of proinflammatory cytokines, similar to the findings obtained in previously reported patients.
CONCLUSION
The presence of the same homozygous novel mutation in IL1RN in 2 unrelated Brazilian patients suggests that this genetic variant may be a founder mutation that has been introduced in the Brazilian population.
Topics: Brazil; Carrier Proteins; Child, Preschool; Female; Hereditary Autoinflammatory Diseases; Homozygote; Humans; Interleukin 1 Receptor Antagonist Protein; Mutation; NLR Family, Pyrin Domain-Containing 3 Protein; Nuclear Proteins; Osteomyelitis; Psoriasis
PubMed: 22127713
DOI: 10.1002/art.30588