Agnès Linglart

Skeletal and extraskeletal disorders of biomineralization

Publisher: Springer Science and Business Media LLC

Date: 16-05-2022

DOI: 10.1038/S41574-022-00682-7

Abstract: The physiological process of biomineralization is complex and deviation from it leads to a variety of diseases. Progress in the past 10 years has enhanced understanding of the genetic, molecular and cellular pathophysiology underlying these disorders sometimes, this knowledge has both facilitated restoration of health and clarified the very nature of biomineralization as it occurs in humans. In this Review, we consider the principal regulators of mineralization and crystallization, and how dysregulation of these processes can lead to human disease. The knowledge acquired to date and gaps still to be filled are highlighted. The disorders of mineralization discussed comprise a broad spectrum of conditions that encompass bone disorders associated with alterations of mineral quantity and quality, as well as disorders of extraskeletal mineralization (hyperphosphataemic familial tumoural calcinosis). Included are disorders of alkaline phosphatase (hypophosphatasia) and phosphate homeostasis (X-linked hypophosphataemic rickets, fluorosis, rickets and osteomalacia). Furthermore, crystallopathies are covered as well as arterial and renal calcification. This Review discusses the current knowledge of biomineralization derived from basic and clinical research and points to future studies that will lead to new therapeutic approaches for biomineralization disorders.

X-linked recessive TLR7 deficiency in ~1% of men under 60 years old with life-threatening COVID-19

Publisher: American Association for the Advancement of Science (AAAS)

Date: 12-08-2021

DOI: 10.1126/SCIIMMUNOL.ABL4348

Abstract: TLR7 and plasmacytoid dendritic cells are essential for type I IFN–dependent immunity to SARS-CoV-2 in the lungs.

Inborn errors of type I IFN immunity in patients with life-threatening COVID-19

Publisher: American Association for the Advancement of Science (AAAS)

Date: 23-10-2020

DOI: 10.1126/SCIENCE.ABD4570

Abstract: The immune system is complex and involves many genes, including those that encode cytokines known as interferons (IFNs). In iduals that lack specific IFNs can be more susceptible to infectious diseases. Furthermore, the autoantibody system d ens IFN response to prevent damage from pathogen-induced inflammation. Two studies now examine the likelihood that genetics affects the risk of severe coronavirus disease 2019 (COVID-19) through components of this system (see the Perspective by Beck and Aksentijevich). Q. Zhang et al. used a candidate gene approach and identified patients with severe COVID-19 who have mutations in genes involved in the regulation of type I and III IFN immunity. They found enrichment of these genes in patients and conclude that genetics may determine the clinical course of the infection. Bastard et al. identified in iduals with high titers of neutralizing autoantibodies against type I IFN-α2 and IFN-ω in about 10% of patients with severe COVID-19 pneumonia. These autoantibodies were not found either in infected people who were asymptomatic or had milder phenotype or in healthy in iduals. Together, these studies identify a means by which in iduals at highest risk of life-threatening COVID-19 can be identified. Science , this issue p. eabd4570 , p. eabd4585 see also p. 404

Continuous Subcutaneous Recombinant Parathyroid Hormone (1–34) Infusion in the Management of Childhood Hypoparathyroidism Associated with Malabsorption

Publisher: S. Karger AG

Date: 19-09-2017

DOI: 10.1159/000479867

Abstract: b i Background/Aims: /i /b Hypoparathyroidism associated with malabsorption can be particularly challenging to manage due to limited and erratic intestinal absorption of calcium and vitamin D analogues, resulting in episodes of hypo- or hypercalcaemia. We evaluated the role of continuous subcutaneous recombinant parathyroid hormone (rhPTH 1–34) infusion (CSPI) in children with hypoparathyroidism associated with intestinal malabsorption resistant to conventional therapy. b i Method: /i /b Four patients (8–13 years of age), with symptomatic hypocalcaemia resistant to conventional therapy, were started on CSPI (follow-up 3–8 years) in two paediatric endocrinology units in Europe. b i Results: /i /b Serum calcium normalized within 48 h of commencing treatment in all 4 patients. An average rhPTH 1–34 dose of 0.4 µg/kg/day resulted in a substantial reduction in symptomatic hypocalcaemia and hypo-/hypercalcaemia-related hospital admissions. An increased alkaline phosphatase activity was noted in the first 6 months on CSPI, indicating an increase in bone turnover. In 2 patients with elevated urinary calcium excretion before CSPI, this normalized in the first year on treatment. No significant side effects were noticed in the short or long term, with patient-reported preference of CSPI over conventional treatment. b i Conclusion: /i /b CSPI is a promising and effective treatment option for managing hypocalcaemia and hyperphosphataemia in children with hypoparathyroidism associated with intestinal malabsorption.

Monitoring guidance for patients with hypophosphatasia treated with asfotase alfa

Publisher: Elsevier BV

Date: 09-2017

DOI: 10.1016/J.YMGME.2017.07.010

Abstract: Hypophosphatasia (HPP) is a rare, inherited, systemic, metabolic disorder caused by autosomal recessive mutations or a single dominant-negative mutation in the gene encoding tissue-nonspecific alkaline phosphatase (TNSALP). The disease is associated with a broad range of signs, symptoms, and complications, including impaired skeletal mineralization, altered calcium and phosphate metabolism, recurrent fractures, pain, respiratory problems, impaired growth and mobility, premature tooth loss, developmental delay, and seizures. Asfotase alfa is a human, recombinant enzyme replacement therapy that is approved in many countries for the treatment of patients with HPP. To address the unmet need for guidance in the monitoring of patients receiving asfotase alfa, an international panel of physicians with experience in diagnosing and managing HPP convened in May 2016 to discuss treatment monitoring parameters. The panel discussions focused on recommendations for assessing and monitoring patients after the decision to treat with asfotase alfa had been made and did not include recommendations for whom to treat. Based on the consensus of panel members, this review provides guidance on the monitoring of patients with HPP during treatment with asfotase alfa, including recommendations for laboratory, efficacy, and safety assessments and the frequency with which these should be performed during the course of treatment. Recommended assessments are based on patient age and include regular monitoring of biochemistry, skeletal radiographs, respiratory function, growth, pain, mobility and motor function, and quality of life. Because of the systemic presentation of HPP, a coordinated, multidisciplinary, team-based, patient-focused approach is recommended in the management of patients receiving asfotase alfa. Monitoring of efficacy and safety outcomes must be tailored to the in idual patient, depending on medical history, clinical manifestations, availability of resources in the clinical setting, and the clinician's professional judgment.

Mutations in SLC20A2 are a major cause of familial idiopathic basal ganglia calcification

Publisher: Springer Science and Business Media LLC

Date: 20-01-2013

DOI: 10.1007/S10048-012-0349-2

Clinical Profiles of Children with Hypophosphatasia prior to Treatment with Enzyme Replacement Therapy: An Observational Analysis from the Global HPP Registry

Publisher: S. Karger AG

Date: 13-07-2023

DOI: 10.1159/000531865

Autoantibodies neutralizing type I IFNs are present in ~4% of uninfected individuals over 70 years old and account for ~20% of COVID-19 deaths

Publisher: American Association for the Advancement of Science (AAAS)

Date: 10-08-2021

DOI: 10.1126/SCIIMMUNOL.ABL4340

Abstract: Autoantibodies neutralizing type I IFNs increase in prevalence over 60 years of age and underlie about 20% of all fatal COVID-19 cases.

Autoantibodies against type I IFNs in patients with life-threatening COVID-19

Publisher: American Association for the Advancement of Science (AAAS)

Date: 23-10-2020

DOI: 10.1126/SCIENCE.ABD4585

Abstract: The immune system is complex and involves many genes, including those that encode cytokines known as interferons (IFNs). In iduals that lack specific IFNs can be more susceptible to infectious diseases. Furthermore, the autoantibody system d ens IFN response to prevent damage from pathogen-induced inflammation. Two studies now examine the likelihood that genetics affects the risk of severe coronavirus disease 2019 (COVID-19) through components of this system (see the Perspective by Beck and Aksentijevich). Q. Zhang et al. used a candidate gene approach and identified patients with severe COVID-19 who have mutations in genes involved in the regulation of type I and III IFN immunity. They found enrichment of these genes in patients and conclude that genetics may determine the clinical course of the infection. Bastard et al. identified in iduals with high titers of neutralizing autoantibodies against type I IFN-α2 and IFN-ω in about 10% of patients with severe COVID-19 pneumonia. These autoantibodies were not found either in infected people who were asymptomatic or had milder phenotype or in healthy in iduals. Together, these studies identify a means by which in iduals at highest risk of life-threatening COVID-19 can be identified. Science , this issue p. eabd4570 , p. eabd4585 see also p. 404

Rare predicted loss-of-function variants of type I IFN immunity genes are associated with life-threatening COVID-19

Publisher: Springer Science and Business Media LLC

Date: 05-04-2023

DOI: 10.1186/S13073-023-01173-8

Abstract: We previously reported that impaired type I IFN activity, due to inborn errors of TLR3- and TLR7-dependent type I interferon (IFN) immunity or to autoantibodies against type I IFN, account for 15–20% of cases of life-threatening COVID-19 in unvaccinated patients. Therefore, the determinants of life-threatening COVID-19 remain to be identified in ~ 80% of cases. We report here a genome-wide rare variant burden association analysis in 3269 unvaccinated patients with life-threatening COVID-19, and 1373 unvaccinated SARS-CoV-2-infected in iduals without pneumonia. Among the 928 patients tested for autoantibodies against type I IFN, a quarter (234) were positive and were excluded. No gene reached genome-wide significance. Under a recessive model, the most significant gene with at-risk variants was TLR7 , with an OR of 27.68 (95%CI 1.5–528.7, P = 1.1 × 10 −4 ) for biochemically loss-of-function (bLOF) variants. We replicated the enrichment in rare predicted LOF (pLOF) variants at 13 influenza susceptibility loci involved in TLR3-dependent type I IFN immunity (OR = 3.70[95%CI 1.3–8.2], P = 2.1 × 10 −4 ). This enrichment was further strengthened by (1) adding the recently reported TYK2 and TLR7 COVID-19 loci, particularly under a recessive model (OR = 19.65[95%CI 2.1–2635.4], P = 3.4 × 10 −3 ), and (2) considering as pLOF branchpoint variants with potentially strong impacts on splicing among the 15 loci (OR = 4.40[9%CI 2.3–8.4], P = 7.7 × 10 −8 ). Finally, the patients with pLOF/bLOF variants at these 15 loci were significantly younger (mean age [SD] = 43.3 [20.3] years) than the other patients (56.0 [17.3] years P = 1.68 × 10 −5 ). Rare variants of TLR3- and TLR7-dependent type I IFN immunity genes can underlie life-threatening COVID-19, particularly with recessive inheritance, in patients under 60 years old.

Author Correction: Skeletal and extraskeletal disorders of biomineralization

Publisher: Springer Science and Business Media LLC

Date: 17-10-2022

DOI: 10.1038/S41574-022-00768-2

Human type I IFN deficiency does not impair B cell response to SARS-CoV-2 mRNA vaccination.

Publisher: Rockefeller University Press

Date: 07-11-2023

DOI: 10.1084/JEM.20220258

Abstract: Inborn and acquired deficits of type I interferon (IFN) immunity predispose to life-threatening COVID-19 pneumonia. We longitudinally profiled the B cell response to mRNA vaccination in SARS-CoV-2 naive patients with inherited TLR7, IRF7, or IFNAR1 deficiency, as well as young patients with autoantibodies neutralizing type I IFNs due to autoimmune polyendocrine syndrome type-1 (APS-1) and older in iduals with age-associated autoantibodies to type I IFNs. The receptor-binding domain spike protein (RBD)-specific memory B cell response in all patients was quantitatively and qualitatively similar to healthy donors. Sustained germinal center responses led to accumulation of somatic hypermutations in immunoglobulin heavy chain genes. The litude and duration of, and viral neutralization by, RBD-specific IgG serological response were also largely unaffected by TLR7, IRF7, or IFNAR1 deficiencies up to 7 mo after vaccination in all patients. These results suggest that induction of type I IFN is not required for efficient generation of a humoral response against SARS-CoV-2 by mRNA vaccines.

Assistance Publique Hôpitaux De Paris

Location: France

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INSERM U1185

Location: France

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Université Paris Descartes

Location: France

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Université Paris-Sorbonne

Location: France

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Université Paris-Sud Faculté De Médecine

Location: France

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