IFIH1 gain‐of‐function has been reported as a cause of a type I interferonopathy encompassing a spectrum of autoinflammatory phenotypes including Aicardi–Goutières syndrome and Singleton Merten ...syndrome. Ascertaining patients through a European and North American collaboration, we set out to describe the molecular, clinical and interferon status of a cohort of individuals with pathogenic heterozygous mutations in IFIH1. We identified 74 individuals from 51 families segregating a total of 27 likely pathogenic mutations in IFIH1. Ten adult individuals, 13.5% of all mutation carriers, were clinically asymptomatic (with seven of these aged over 50 years). All mutations were associated with enhanced type I interferon signaling, including six variants (22%) which were predicted as benign according to multiple in silico pathogenicity programs. The identified mutations cluster close to the ATP binding region of the protein. These data confirm variable expression and nonpenetrance as important characteristics of the IFIH1 genotype, a consistent association with enhanced type I interferon signaling, and a common mutational mechanism involving increased RNA binding affinity or decreased efficiency of ATP hydrolysis and filament disassembly rate.
We describe a case of coma-related hyperammonemia in a woman presenting with severe edematous malnutrition (Kwashiorkor-like), without underlying hepatic disease. Our main hypothesis is that the ...patient developed a functional urea cycle disorder, due to the inability to synthesize N-acetylglutamate which is the activator of the first enzymes (carbamoyl phosphate synthetase) of urea cycle, in a context of severe deficiency of essential amino acids and of acetyl-CoA. Severe hyperammonemia is a medical emergency exposing to the risk of cerebral edema. Urgent treatment should interrupt protein intake, stimulate protein anabolism, and remove ammonia from the blood using renal replacement therapy and ammonia scavengers. Hyperammonemia should be searched in case of unexplained coma, even among patients without hepatic disorder, in particular among young patients. Hyperammonemia should also be searched among patients with severe protein-calorie malnutrition.
Initial reports on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in children suggested that very young age and comorbidities may increase risk of severe evolution, but these ...findings remained to be confirmed. We aimed to analyze the clinical spectrum of hospitalized pediatric SARS-CoV-2 infection and predictors of severe disease evolution.
We conducted a French national prospective surveillance of children hospitalized with SARS-CoV-2 infection. We included all children with confirmed SARS-CoV-2 infection in 60 hospitals during February 15 to June 1, 2020. The main outcome was the proportion of children with severe disease, defined by hemodynamic or ventilatory (invasive or not) support requirement.
We included 397 hospitalized children with SARS-CoV-2 infection. We identified several clinical patterns, ranging from paucisymptomatic children, admitted for surveillance, to lower respiratory tract infection or multisystem inflammatory syndrome in children. Children <90 days old accounted for 37% of cases (145 of 397), but only 4 (3%) had severe disease. Excluding children with multisystem inflammatory syndrome in children (
= 29) and hospitalized for a diagnosis not related to SARS-CoV-2 (
= 62), 23 of 306 (11%) children had severe disease, including 6 deaths. Factors independently associated with severity were age ≥10 years (odds ratio OR = 3.4, 95% confidence interval: 1.1-10.3), hypoxemia (OR = 8.9 2.6-29.7), C-reactive protein level ≥80 mg/L (OR = 6.6 1.4-27.5).
In contrast with preliminary reports, young age was not an independent factor associated with severe SARS-CoV-2 infection, and children <90 days old were at the lowest risk of severe disease evolution. This may help physicians to better identify risk of severe disease progression in children.
The emergence of next-generation sequencing enabled a cost-effective and straightforward diagnostic approach to genetic disorders using clinical exome sequencing (CES) panels. We performed a ...retrospective observational study to assess the diagnostic yield of CES as a first-tier genetic test in 128 consecutive pediatric patients addressed to a referral center in the North-East of France for a suspected genetic disorder, mainly an inborn error of metabolism between January 2016 and August 2020. CES was performed using the TruSight One (4811 genes) or the TruSight One expanded (6699 genes) panel on an Illumina sequencing platform. The median age was 6.5 years (IQR 2.0–12.0) with 43% of males (55/128), and the median disease duration was 7 months (IQR 1–47). In the whole analysis, the CES diagnostic yield was 55% (70/128). The median test-to-report time was 5 months (IQR 4–7). According to CES indications, the CES diagnostic yields were 81% (21/26) for hyperlipidemia, 75% (6/8) for osteogenesis imperfecta, 64% (25/39) for metabolic disorders, 39% (10/26) for neurological disorders, and 28% (8/29) for the subgroup of patients with miscellaneous conditions. Our results demonstrate the usefulness of a CES-based diagnosis as a first-tier genetic test to establish a molecular diagnosis in pediatric patients with a suspected genetic disorder with a median test-to-report time of 5 months. It highlights the importance of a close interaction between the pediatrician with expertise in genetic disorders and the molecular medicine physician to optimize both CES indication and interpretation.
Graphic abstract
Diagnostic yield of clinical exome sequencing (CES) as a first-tier genetic test for diagnosing genetic disorders in 128 consecutive pediatric patients referred to a reference center in the North-East of France for a suspected genetic disorder, mainly an inborn error of metabolism between January 2016 and August 2020. The CES diagnostic yields are reported in the whole population and patients’ subgroups (hyperlipidemia, osteogenesis imperfecta, metabolic diseases, neurological disorders, miscellaneous conditions) (Icons made by Flaticon, flaticon.com; CC-BY-3.0).
Purpose Renal replacement therapy (RRT) is used in hyperammonemia to reduce the concentration of ammonia in the blood. In the case of plasma hyperosmolarity, RRT can also rapidly decrease plasma ...osmolarity, which may increase cerebral edema in these patients and favor the occurrence of brain herniation. Methods We conducted a retrospective clinical study in a tertiary care university-affiliated hospital. All patients admitted in a Pediatric Intensive Care Unit (PICU), less than 18 years old with ammonemia >150 µmol/L and who underwent RRT between January 2015 and June 2023 were included. We collected data on plasma osmolarity levels, osmolar gap and blood ammonia levels before and during RRT. Results Eleven patients were included (10 with acute liver failure and 1 with a urea cycle disorders). Their mean age was 36.2 months. Before RRT, the median highest measured osmolarity was 320 (305–324) mOsm/L, whereas the median calculated osmolarity was 303 (293–314) mOsm/L, corresponding to an osmolar gap of 14 mOsm/L. Ammonia blood level over 400 µmol/L are significantly associated with higher plasma osmolarity ( P -Value <0.001). In one case, a patient had a brain herniation episode after a quick osmolar drop. This episode was reversed by the administration of hyperosmolar agents and the temporary suspension of RRT. Conclusion This study highlights the hyperosmolarity and high osmolar gap that occur in children with hyperammonemia. A careful monitoring and control of plasma osmolarity evolution may alert clinician on the risk of occurrence of neurological complication such as brain herniation.
TANGO2 disease is a severe inherited disorder associating multiple symptoms such as metabolic crises, encephalopathy, cardiac arrhythmias, and hypothyroidism. The mechanism of action of TANGO2 is ...currently unknown. Here, we describe a cohort of 20 French patients bearing mutations in the TANGO2 gene. We found that the main clinical presentation was the association of neurodevelopmental delay (n = 17), acute metabolic crises (n = 17) and hypothyroidism (n = 12), with a large intrafamilial clinical variability. Metabolic crises included rhabdomyolysis (15/17), neurological symptoms (14/17), and cardiac features (12/17; long QT (n = 10), Brugada pattern (n = 2), cardiac arrhythmia (n = 6)) that required intensive care. We show previously uncharacterized triggers of metabolic crises in TANGO2 patients, such as some anesthetics and possibly l‐carnitine. Unexpectedly, plasma acylcarnitines, plasma FGF‐21, muscle histology, and mitochondrial spectrometry were mostly normal. Moreover, in patients' primary myoblasts, palmitate and glutamine oxidation rates, and the mitochondrial network were also normal. Finally, we found variable mitochondrial respiration and defective clearance of oxidized DNA upon cycles of starvation and refeeding. We conclude that TANGO2 disease is a life‐threatening disease that needs specific cardiac management and anesthesia protocol. Mechanistically, TANGO2 disease is unlikely to originate from a primary mitochondrial defect. Rather, we suggest that mitochondrial defects are secondary to strong extrinsic triggers in TANGO2 deficient patients.
Osteoporosis is a common complication of cerebral palsy and Rett’s syndrome. It is responsible for multiple fractures, bone pain, and impaired quality of life. In case of Rett’s syndrome, a specific ...dysfunction of osteoblasts causes bone fragility. We observed the effects of annual zoledronic acid (ZA) infusion in a cohort of children with cerebral palsy and Rett’s syndrome. 27 children under 18 years (19 with cerebral palsy and 8 girls with Rett syndrome confirmed by MCEP2 mutation) were treated with an annual injection of 0.1 mg/kg (max 4 mg) of ZA. Calcium and vitamin D were combined in all patients from the first injection of ZA. Dental examination was performed before treatment. Data were analyzed retrospectively. Bone mineral density was measured at diagnosis and yearly thereafter. Bone mass density (BMD) is decreased in patient with cerebral palsy and RS. One year after injection of ZA, we observe an increase of Lumbar spine BMD from − 2.99 to − 2.14 SD (
p
< 0.0001) and femoral BMD from − 4.26 to − 3.32 SD (
p
< 0.001) In the subgroup of patient with Rett syndrome, we also observe an increase from − 3.27 to 2.50 SD (
p
= 0.018) of Lumbar spine BMD. No fractures have been observed in our cohort since the first infusion. Side effects (flu-like syndrome and hypocalcemia) were more common in younger patients and after the first infusion. No serious complications were noticed. This study confirms the efficacy and the safety of an annual injection of ZA to improve bone status in children with cerebral palsy and Rett syndrome. No severe adverse effects were observed.
La phénylcétonurie Wiedemann, Arnaud; Oussalah, Abderrahim; Jeannesson, Élise ...
M.S. Médecine sciences,
08/2020, Letnik:
36, Številka:
8-9
Journal Article
Recenzirano
Odprti dostop
Le pronostic de la phénylcétonurie (PCU) a été transformé par le dépistage néonatal et la prise en charge diététique
via
un apport contrôlé en phénylalanine. Ce traitement doit être suivi toute la ...vie durant, ce qui pose des problèmes de compliances importants. Un traitement médicamenteux par saproptérine (ou BH4) est venu apporter une aide à un pourcentage réduit de patients qui répondent à ce médicament. Une enzymothérapie par voie sous-cutanée est disponible aux États-Unis et a obtenue une AMM européenne, mais génère des effets secondaires importants, ce qui en limite l’efficacité. De nouvelles options thérapeutiques de la PCU sont actuellement en développement, en particulier par thérapie génique. Le but de cet article est de faire le point sur la physiopathologie et sur les différentes nouvelles modalités thérapeutiques actuellement en développement.
The prognosis for phenylketonuria (PKU) has been improved by neonatal screening and dietary management via a low-phenylalanine diet. This treatment must be followed throughout life, which induces severe compliance problems. Drug treatment with sapropterin (or BH4) has come to help a reduced percentage of patients who respond to this drug. A subcutaneous enzyme therapy is available in the USA and has obtained European marketing authorization, but generates significant side effects, which limits its effectiveness. New therapeutic options for PKU are currently being developed, in particular gene therapy. The purpose of this article is to take stock of the pathophysiology and the various new therapeutic modalities currently in development.
Signal sequence receptor protein 4 (SSR4) is a subunit of the translocon‐associated protein complex, which participates in the translocation of proteins across the endoplasmic reticulum membrane, ...enhancing the efficiency of N‐linked glycosylation. Pathogenic variants in SSR4 cause a congenital disorder of glycosylation: SSR4–congenital disorders of glycosylation (CDG). We describe three SSR4–CDG boys and review the previously reported. All subjects presented with hypotonia, failure to thrive, developmental delay, and dysmorphic traits and showed a type 1 serum sialotransferrin profile, facilitating the diagnosis. Genetic confirmation of this X‐linked CDG revealed one de novo hemizygous deletion, one maternally inherited deletion, and one de novo nonsense mutation of SSR4. The present subjects highlight the similarities with a connective tissue disorder (redundant skin, joint laxity, blue sclerae, and vascular tortuosity). The connective tissue problems are relevant, and require preventive rehabilitation measures. As an X‐linked disorder, genetic counseling is essential.
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