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Identification of rare genetic variants in patients with intellectual disability ( ID) has been greatly accelerated by advances in next generation sequencing technologies. However, due to small numbers of patients, the complete phenotypic spectrum associated with pathogenic variants in single genes is still emerging. Among these genes is ZBTB18 ( ZNF238), which is deleted in patients with 1q43q44 microdeletions who typically present with ID, microcephaly, corpus callosum ( CC) abnormalities, and seizures. Here we provide additional evidence for haploinsufficiency or dysfunction of the ZBTB18 gene as the cause of ID in five unrelated patients with variable syndromic features who underwent whole exome sequencing revealing separate de novo pathogenic or likely pathogenic variants in ZBTB18 (two missense alterations and three truncating alterations). The neuroimaging findings in our cohort ( CC hypoplasia seen in 4/4 of our patients who underwent MRI) lend further support for ZBTB18 as a critical gene for CC abnormalities. A similar phenotype of microcephaly, CC agenesis, and cerebellar vermis hypoplasia has been reported in mice with central nervous system-specific knockout of Zbtb18. Our five patients, in addition to the previously described cases of de novo ZBTB18 variants, add to knowledge about the phenotypic spectrum associated with ZBTB18 haploinsufficiency/dysfunction. [ABSTRACT FROM AUTHOR]

Abstract: The ammonia selectivity during the cycling NOx storage reduction process over a model Pt/Ba/Al2O3 catalyst was studied. Firstly, it was demonstrated that, whereas the presence of water or carbon dioxide in the gas mixture have a negative effect on the storage step, the effect of these components have different impacts on the NOx efficiency. Due to their involvement in the reverse water gas shift (RWGS) reaction, the absence of water in the gas mixture leads to a drop of the NOx removal whereas without CO2, an increase of the NOx conversion is observed. It was also showed that the reducer (H2) conversion during the short excursion in rich condition is directly correlated to the NH3 emission. NH3 is emitted since hydrogen is not fully converted, whatever the NOx conversion rate. The ammonia pathway is clearly demonstrated and it was claim that, when H2 remains in the reaction mixture, the ammonia production rate is higher than the ammonia reaction with the remaining NOx in order to form N2. [Copyright &y& Elsevier]

Purpose: Biallelic pathogenic variants in the gene encoding the ATP-binding cassette transporter ABCA4 are the leading cause of irreversible vision loss in inherited retinal dystrophies (IRDs). Interpretation of ABCA4 variants is challenging, due to cis-modifying and hypomorphic variants. We have previously detected 10 missense variants of unknown significance (VUS) in patients with suspected ABCA4-retinal dystrophies (ABCA4-RDs) in Norway. In this study, we functionally characterized the VUS to aid interpretation of the variants and to determine if they are associated with the disease., Methods: The ABCA4 VUS were expressed in HEK293T cells and the ABCA4 expression level and ATPase activity were determined and correlated with the patients' phenotype. The functional data further used for reclassification of the VUS following the American College of Medical Genetics and Genomics (ACMG) guidelines., Results: Of the 10 VUSs, 2 variants, Cys205Phe and Asn415Thr, were categorized as functionally severe. The age at presentation in the 2 patients carrying these variants was divergent and seemed to be driven by the patients' second pathogenic variants Gly1961Glu and c.5461-10T>C, respectively. Three variants, Val643Gly, Pro799Leu, and Val1433Ile were categorized as functionally moderate, and were found in patients with intermediate/late age at presentation. The remaining five variants were categorized as functionally normal/mild. Based on our data, c.614G>T p.(Cys205Phe), c.1244A>C p.(Asn415Thr), and c.2396C>T p.(Pro799Leu) were reclassified to (likely) pathogenic, while 4 of the functionally normal/mild variants could be reclassified to likely benign., Conclusions: Functional analyses of ABCA4 variants are a helpful tool in variant classification and enable us to better predict the disease severity in patients with ABCA4-RDs.

We aimed to provide a detailed phenotypic description of status epilepticus (SE) in a large cohort of patients with POLG disease and identify prognostic biomarkers to improve the management of this life-threatening condition. In a multinational, retrospective study with data on patients with POLG disease from seven European countries, we identified those who had SE. The age of SE onset, accompanying clinical, laboratory, imaging and genetic findings were analysed. One hundred and ninety-five patients with genetically confirmed POLG disease were recruited, of whom 67% (130/194) had epilepsy. SE was identified in 77% (97/126), with a median age of SE onset of 7 years. SE was the presenting symptom of the disease in 43% (40/93) of those with SE, while 57% (53/93) developed SE during the disease course. Convulsive SE was reported in 97% (91/94) followed by epilepsia partialis continua in 67% (56/84). Liver impairment 78% (74/95), ataxia 69% (60/87), stroke-like episodes 57% (50/88), were the major comorbidities. In the majority (66%; 57/86) with SE this became refractory or super-refractory. The presence of seizures was associated with significantly higher mortality compared to those without (P ≤ 0.001). The median time from SE debut to death was 5 months. SE is a major clinical feature of POLG disease in early and juvenile to adult-onset disease and can be the presenting feature or arise as part of a multisystem disease. It is associated with high morbidity and mortality, with the majority of patients with SE going on to develop refractory or super-refractory SE., (© 2024. The Author(s).)

Purpose: Congenital hyperinsulinism (CHI) is a rare, monogenic disease characterized by excessive insulin secretion. We aimed to evaluate all probands with suspected CHI in Norway registered over the past two decades., Methods: The study included 98 probands. Clinical data were cumulated from medical records. All probands were screened for variants in the genes ABCC8 and KCNJ11. Other CHI-related genes were Sanger-sequenced as indicated by the patients' phenotype (N=75) or analyzed by next-generation sequencing employing a panel of 30 CHI-related genes (N=23)., Results: Twenty-one probands (21%) received a diagnosis other than CHI, the most common being idiopathic ketotic hypoglycemia (9%) or syndromic hyperinsulinism (4%). In the final cohort of 77 CHI probands, genetic findings were revealed in 46 (60%). ABCC8 variants were most common (N=40) and five novel variants were identified. One proband harbored both the pathogenic GCK variant p.(Ala456Val) and the ABCC8 variant p.(Gly505Cys). Although most ABCC8 variants caused immediate disease onset with severe hypoglycemia and were diazoxide-unresponsive, eight probands had a heterozygous, apparently dominant variant with milder phenotype. Two probands had pathogenic variants in GLUD1, whereas variants in HADH, HNF4A, KCNJ11, and HK1 were identified in one proband each, the latter being non-coding. Neurologic sequelae were reported in 53% of the CHI probands. Of non-surgically treated probands, 43% had spontaneous resolution. The minimum birth prevalence of CHI in Norway is 1:19,400 live births., Main Conclusions: Individuals with disease-causing ABCC8 variants dominated our cohort. Patients with known genetic etiology had earlier and more severe disease-onset than genetically unsolved patients., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society.)

Objective: To investigate the prevalence and natural history of POLG disease in the Norwegian population., Methods: A national, population-based, retrospective study using demographic, clinical, and genetic data of patients with genetically confirmed POLG disease. The patients were diagnosed between 2002 and 2022, and were included into the Norwegian POLG Patient Registry. Patients were stratified according to age at disease onset (early <12 years, juvenile to adult 12-40 years, late ≥40 years) and resident region., Results: Ninety-one patients were included. The point prevalence of POLG disease was 1:149,253. Birth prevalence was 1:48,780. Median age at clinical onset was 16 years (range: 2 months to 70 years). Onset occurred early in 35% (32 out of 91), juvenile-adult in 55% (50 out of 91) and late in 10% (9 out of 91). A distinct seasonal pattern in disease onset was observed, with 57% (52 out of 91) presenting between May and August. Forty-five patients (49%) had acute exacerbations that required intensive care, and this affected 72% of those in the early-onset group. The mortality rate was 54% (49 out of 91), with a median time from disease onset to death of 3 years (range: 1 month to 36 years)., Interpretation: We provide the point prevalence and birth prevalence of POLG disease in the first nationwide study in which epidemiological and clinical data were integrated. Seasonal variations in clinical onset may offer valuable insights into disease mechanisms and modifying factors. The findings from this study are crucial for quantifying the disease burden, and contribute to evidence-based healthcare planning., (© 2024 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Indo-Pacific tropical island streams are home to freshwater pipefish ( Microphis spp., Syngnathidae). Otoliths were used to uncover life history traits in four species, including a New Caledonian endemic. All four species present the same methodological challenge: their otoliths are small, fragile and mute for growth marks using basic observation tools. Strontium (Sr) is calcium substituent in the mineral lattice, driven by salinity conditions, and thus useful to study diadromous migrations. Synchrotron-based scanning X-ray fluorescence 2D high-resolution mapping allowed us to tackle the global and hyperfine strontium (Sr) distribution. We developed analytical imaging processes to retrieve biological information from otoliths from the data generated via synchrotron analysis. We uncovered plasticity in the life cycle: all species were amphidromous, apart from some freshwater residents from New Caledonia. Understanding life cycle modalities is crucial to categorize species distribution limits and to implement adapted conservation measures, especially when endemic species are at stake. 2D fine-scale images outlined the heterogeneity of Sr distribution: in addition to the trivial Sr incorporation driven by environmental ionic conditions, there is an unusual mosaic arrangement of Sr distribution and we hypothesize that biological control, especially growth during the early life stages, may sometimes overrule stoichiometry. This shows that it is worth studying otolith formation and element integration at imbricated scales, and our methods and results provide a strong basis for future works and prospects in otolith science.

Precise regulation of gene expression is important for correct neurodevelopment. 9q34.3 deletions affecting the EHMT1 gene result in a syndromic neurodevelopmental disorder named Kleefstra syndrome. In contrast, duplications of the 9q34.3 locus encompassing EHMT1 have been suggested to cause developmental disorders, but only limited information has been available. We have identified 15 individuals from 10 unrelated families, with 9q34.3 duplications <1.5 Mb in size, encompassing EHMT1 entirely. Clinical features included mild developmental delay, mild intellectual disability or learning problems, autism spectrum disorder, and behavior problems. The individuals did not consistently display dysmorphic features, congenital anomalies, or growth abnormalities. DNA methylation analysis revealed a weak DNAm profile for the cases with 9q34.3 duplication encompassing EHMT1, which could segregate the majority of the affected cases from controls. This study shows that individuals with 9q34.3 duplications including EHMT1 gene present with mild non-syndromic neurodevelopmental disorders and DNA methylation changes different from Kleefstra syndrome., (© 2024 The Authors. Clinical Genetics published by John Wiley & Sons Ltd.)

Molybdenum cofactor deficiency classically presents in neonates with intractable seizures; however, milder cases generally present before age 2 years with developmental delays and may go undiagnosed. Early diagnosis, and safe, US Food and Drug Administration-approved substrate replacement are critical to preserve neurologic function. This article discusses 2 children who presented with late-onset molybdenum cofactor deficiency type A.

Calmodulin-binding transcriptional activator 1 (CAMTA1) is highly expressed in the brain and plays a role in cell cycle regulation, cell differentiation, regulation of long-term memory, and initial development, maturation, and survival of cerebellar neurons. The existence of human neurological phenotypes, including cerebellar dysfunction with variable cognitive and behavioral abnormalities (CECBA), associated with CAMTA1 variants, has further supported its role in brain functions. In this study, we phenotypically and molecularly characterize the largest cohort of individuals (n = 26) with 23 novel CAMTA1 variants (frameshift-7, nonsense-6, splicing-1, initiation codon-1, missense-5, and intragenic deletions-3) and compare the findings with all previously reported cases (total = 53). We show that the most notable phenotypic findings are developmental delay/intellectual disability, unsteady or uncoordinated gait, hypotonia, behavioral problems, and eye abnormalities. In addition, there is a high incidence of dysarthria, dysgraphia, microcephaly, gastrointestinal abnormalities, sleep difficulties, and nonspecific brain MRI findings; a few of which have been under-reported. More than one third of the variants in this cohort were inherited from an asymptomatic or mildly affected parent suggesting reduced penetrance and variable expressivity. Our cohort provides a comprehensive characterization of the spectrum of phenotypes and genotypes among individuals with CECBA and the large data will facilitate counseling and formulating management plans and surveillance recommendations for these individuals., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Study Question: Is it possible to find the cause of primary ovarian insufficiency (POI) in more women by extensive screening?, Summary Answer: Adding next generation sequencing techniques including a POI-associated gene panel, extended whole exome sequencing data, as well as specific autoantibody assays to the recommended diagnostic investigations increased the determination of a potential etiological diagnosis of POI from 11% to 41%., What Is Known Already: POI affects ∼1% of women. Clinical presentations and pathogenic mechanisms are heterogeneous and include genetic, autoimmune, and environmental factors, but the underlying etiology remains unknown in the majority of cases., Study Design, Size, Duration: Prospective cross-sectional study of 100 women with newly diagnosed POI of unknown cause consecutively referred to Haukeland University Hospital, Bergen, Norway, January 2019 to December 2021., Participants/materials, Setting, Methods: In addition to standard recommended diagnostic investigations including screening for chromosomal anomalies and premutations in the fragile X mental retardation 1 gene (FMR1) we used whole exome sequencing, including targeted analysis of 103 ovarian-related genes, and assays of autoantibodies against steroid cell antigens., Main Results and the Role of Chance: We identified chromosomal aberrations in 8%, FMR1 premutations in 3%, genetic variants related to POI in 16%, and autoimmune POI in 3%. Furthermore in 11% we identified POI associated genetic Variants of unknown signifcance (VUS). A homozygous pathogenic variant in the ZSWIM7 gene (NM&#95;001042697.2) was found in two women, corroborating this as a novel cause of monogenic POI. No associations between phenotypes and genotypes were found., Limitations, Reasons for Caution: Use of candidate genetic and autoimmune markers limit the possibility to discover new markers. To further investigate the genetic variants, family studies would have been useful. We found a relatively high proportion of genetic variants in women from Africa and lack of genetic diversity in the genomic databases can impact diagnostic accuracy., Wider Implications of the Findings: Since no specific clinical or biochemical markers predicted the underlying cause of POI discussion of which tests should be part of diagnostic screening in clinical practice remains open. New technology has altered the availability and effectiveness of genetic testing, and cost-effectiveness analyses are required to aid sustainable diagnostics., Study Funding/competing Interest(s): The study was supported by grants and fellowships from Stiftelsen Kristian Gerhard Jebsen, the Novonordisk Foundation, the Norwegian Research Council, University of Bergen, and the Regional Health Authorities of Western Norway. The authors declare no conflict of interest., Trial Registration Number: NCT04082169., (© The Author(s) 2023. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology.)