PURPOSE. To investigate the plasma concentration of nicotinamide in primary open-angle glaucoma (POAG). METHODS. Plasma of 34 POAG individuals was compared to that of 30 age-and sex-matched controls using a semiquantitative method based on liquid chromatography coupled to highresolution mass spectrometry. Subsequently, an independent quantitative method, based on liquid chromatography coupled to mass spectrometry, was used to assess nicotinamide concentration in the plasma from the same initial cohort and from a replicative cohort of 20 POAG individuals and 15 controls. RESULTS. Using the semiquantitative method, the plasma nicotinamide concentration was significantly lower in the initial cohort of POAG individuals compared to controls and further confirmed in the same cohort, using the targeted quantitative method, with mean concentrations of 0.14 lM (median: 0.12 lM; range, 0.06-0.28 lM) in the POAG group (À30%; P ¼ 0.022) and 0.19 lM (median: 0.18 lM; range, 0.08-0.47 lM) in the control group. The quantitative dosage also disclosed a significantly lower plasma nicotinamide concentration (À33%; P ¼ 0.011) in the replicative cohort with mean concentrations of 0.14 lM (median: 0.14 lM; range, 0.09-0.25 lM) in the POAG group, and 0.19 lM (median: 0.21 lM; range, 0.09-0.26 lM) in the control group. CONCLUSIONS. Glaucoma is associated with lower plasmatic nicotinamide levels, compared to controls, suggesting that nicotinamide supplementation might become a future therapeutic strategy. Further studies are needed, in larger cohorts, to confirm these preliminary findings.

Glaucoma is an age related disease characterized by the progressive loss of retinal ganglion cells, which are the neurons that transduce the visual information from the retina to the brain. It is the leading cause of irreversible blindness worldwide. To gain further insights into primary open-angle glaucoma (POAG) pathophysiology, we performed a non-targeted metabolomics analysis on the plasma from POAG patients (n = 34) and age- and sex-matched controls (n = 30). We investigated the differential signature of POAG plasma compared to controls, using liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS). A data mining strategy, combining a filtering method with threshold criterion, a wrapper method with iterative selection, and an embedded method with penalization constraint, was used. These strategies are most often used separately in metabolomics studies, with each of them having their own limitations. We opted for a synergistic approach as a mean to unravel the most relevant metabolomics signature. We identified a set of nine metabolites, namely: nicotinamide, hypoxanthine, xanthine, and 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline with decreased concentrations and N-acetyl-L-Leucine, arginine, RAC-glycerol 1-myristate, 1-oleoyl-RAC-glycerol, cystathionine with increased concentrations in POAG; the modification of nicotinamide, N-acetyl-L-Leucine, and arginine concentrations being the most discriminant. Our findings open up therapeutic perspectives for the diagnosis and treatment of POAG.

Pathogenic variants of the nuclear receptor subfamily 2 group F member 1 gene (NR2F1) are responsible for Bosch–Boonstra–Schaaf optic atrophy syndrome (BBSOAS), an autosomal dominant disorder characterized by optic atrophy associated with developmental delay and intellectual disability, but with a clinical presentation which appears to be multifaceted. We created the first public locus‐specific database dedicated to NR2F1. All variants and clinical cases reported in the literature, as well as new unpublished cases, were integrated into the database using standard nomenclature to describe both molecular and phenotypic anomalies. We subsequently pursued a comprehensive approach based on computed representation and analysis suggesting a refinement of the BBSOAS clinical description with respect to neurological features and the inclusion of additional signs of hypotonia and feeding difficulties. This database is fully accessible for both clinician and molecular biologists and should prove useful in further refining the clinical synopsis of NR2F1 as new data is recorded.

PURPOSE: To investigate the plasma concentration of nicotinamide in primary openangle glaucoma (POAG).DESIGN: Case-control study METHODS: Plasma of 34 POAG individuals were compared to that of 30 age-and sexmatched controls using a semi-quantitative method based on liquid chromatography coupled to high-resolution mass spectrometry. Subsequently, an independent quantitative method, based on liquid chromatography coupled to mass spectrometry, was used to assess nicotinamide concentration in the plasma from the same initial cohort and from a replicative cohort of 20 POAG individuals and 15 controls.RESULTS: Using the semi-quantitative method, the plasma nicotinamide concentration was significantly lower in the initial cohort of POAG individuals compared to controls (-36 %, False Discovery Rate corrected p-value = 0.0027) and further confirmed in the same cohort, using the targeted quantitative method, with mean concentrations of 0.14 µM (median: 0.12 µM; range: 0.06-0.28 µM) in the POAG group (-30 %; p = 0.022), and 0.19 µM (median: 0.18 µM; range: 0.08-0.47 µM) in the control group. The quantitative dosage also disclosed a significantly lower plasma nicotinamide concentration (-33 %; p = 0.011) in the replicative cohort with mean concentrations of 0.14 µM (median: 0.14 µM; range: 0.09-0.25 µM) in the POAG group, and 0.19 µM (median: 0.21 µM; range: 0.09-0.26 µM) in the control group.CONCLUSIONS: Glaucoma is associated with lower plasmatic nicotinamide levels, compared to controls, suggesting that nicotinamide supplementation might become a future therapeutic strategy. Further studies are needed, in larger cohorts, to confirm these preliminary findings.

Pathogenic variants of the aconitase 2 gene (ACO2) are responsible for a broad clinical spectrum involving optic nerve degeneration, ranging from isolated optic neuropathy with recessive or dominant inheritance, to complex neurodegenerative syndromes with recessive transmission. We created the first public locus-specific database (LSDB) dedicated to ACO2 within the “Global Variome shared LOVD” using exclusively the Human Phenotype Ontology (HPO), a standard vocabulary for describing phenotypic abnormalities. All the variants and clinical cases listed in the literature were incorporated into the database, from which we produced a dataset. We followed a rational and comprehensive approach based on the HPO thesaurus, demonstrating that ACO2 patients should not be classified separately between isolated and syndromic cases. Our data highlight that certain syndromic patients do not have optic neuropathy and provide support for the classification of the recurrent pathogenic variants c.220C>G and c.336C>G as likely pathogenic. Overall, our data records demonstrate that the clinical spectrum of ACO2 should be considered as a continuum of symptoms and refines the classification of some common variants.