References of "BOEMER, François"
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See detailFalsos positivos de C5-carnitina elevada en cribado neonatal: A que son debidos?
Yahyaoui, Raquel; Rueda; Dayaldasani, Anita et al

in Medicina Clinica (2014)

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See detailMitochondrial encephalomyopathy with cytochrome c oxidase deficiency caused by a novel mutation in the MTCO1 gene.
Debray, François-Guillaume ULg; Seneca, Sara; Gonce, Michel et al

in Mitochondrion (2014)

Cytochrome c oxidase (COX) deficiency is one of the most common respiratory chain deficiencies. A woman was presented at the age of 18y with acute loss of consciousness, non-convulsive status epilepticus ... [more ▼]

Cytochrome c oxidase (COX) deficiency is one of the most common respiratory chain deficiencies. A woman was presented at the age of 18y with acute loss of consciousness, non-convulsive status epilepticus, slow neurological deterioration, transient cortical blindness, exercise intolerance, muscle weakness, hearing loss, cataract and cognitive decline. Muscle biopsy revealed ragged-red fibers, COX negative fibers and a significant decreased activity of complex IV in a homogenate. Using next generation massive parallel sequencing of the mtDNA, a novel heteroplasmic mutation was identified in MTCO1, m.7402delC, causing frameshift and a premature termination codon. Single fiber PCR showed co-segregation of high mutant load in COX negative fibers. Mutation in mitochondrially encoded complex IV subunits should be considered in mitochondrial encephalomyopathies and COX negative fibers after the common mtDNA mutations have been excluded. [less ▲]

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See detailSurprising causes of C5-carnitine false positive results in newborn screening.
BOEMER, François ULg; SCHOOS, Roland ULg; de HALLEUX, Virginie ULg et al

in Molecular genetics and metabolism (2014), 111(1), 52-4

During an 18-month period, we noticed an alarming increase of newborn screening false positivity rate in identifying isovaleric acidemia. In 50 of 50 newborns presenting elevated C5-carnitine, we ... [more ▼]

During an 18-month period, we noticed an alarming increase of newborn screening false positivity rate in identifying isovaleric acidemia. In 50 of 50 newborns presenting elevated C5-carnitine, we confirmed the presence of pivaloylcarnitine. Exogenous pivalate administration had been previously identified as the causal agent of this concern. No pivalic-ester prodrug is commercially available in Belgium, but pivalic derivates are also used in the cosmetic industry as emollient under the term "neopentanoate". We have identified neopentanoate-esters in a nipple-fissure unguent that was provided to young mothers. Ceasing distribution of this product hugely reduced the C5-carnitine false positivity rate. [less ▲]

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See detailBLOOD GROUPS, HEMOGLOBIN PHENOTYPES AND CLINICAL DISORDERS OF CONSANGUINEOUS YANSI POPULATION
Munlemvo Mavanga, Nana ULg; BOEMER, François ULg; SEIDEL, Laurence ULg et al

in World Journal of Hematology (2013), 2(4), 109-114

AIM To study frequency of blood groups, prevalence of sickle-cell anemia trait and glucose-6-phosphate dehydrogenase deficiency, among consanguineous Yansi tribe. METHODS A total of 525 blood samples were ... [more ▼]

AIM To study frequency of blood groups, prevalence of sickle-cell anemia trait and glucose-6-phosphate dehydrogenase deficiency, among consanguineous Yansi tribe. METHODS A total of 525 blood samples were collected, of which 256 among the Yansi population, and 269 for the unrelated control group in the Bandundu province of Democratic Republic of Congo. Blood group antigens were determined in the following systems: ABO, Rh, Kell, Duffy, Kidd and MNS. Blood grouping and extended phenotype tests were performed according to standard immunohematological procedures. Spot tests and tandem mass spectrometry were used respectively for the assessment of glucose-6-phosphate dehydrogenase deficiency and sickle-cell anemia trait. RESULTS The frequency of ABO phenotypes conformed to the following order O>A>B>AB with notably 62.5, 23.8, 12.1 and 1.6% for the Yansi, and 54.6, 27.5, 14.1 and 3.7% for the unrelated control group, respectively (P=0.19). As for the Rh phenotypes, the most frequent were ccD.ee, ccD.Ee, CcD.ee, corresponding to 71.5, 12.1 and 12.1% for the Yansi, and 70.6, 15.6 and 8.2%, for the unrelated control group (P=0.27). The frequency of MN and Ss phenotypes were statistically different between groups (P=0.0021 and P=0.0006). G6PD deficiency was observed in 11.3% of subjects in the Yansi group, and in 12.4% of controls (P = 0.74). The sickle-cell anemia trait was present in 22.4% of Yansi subjects and 17.8% in the control group (P=0.24). Miscarriages and deaths in young age were more common among Yansi people. CONCLUSION This study shows a significant difference in MNS blood group distribution between the Yansi tribe and a control population. The distribution of other blood groups and the prevalence of hemoglobinopathies did not differ in the Yansi tribe. [less ▲]

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See detailEvaluation of Physiological Amino Acids Profiling by Tandem Mass Spectrometry
Filee, Romain; Schoos, Roland; BOEMER, François ULg

in Journal of Inherited Metabolic Disease Reports (2013)

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See detailHETEROGENOUS CLINICAL AND LABORATORY PRESENTATIONS IN MAD DEFICIENCY
BOEMER, François ULg; SCHOOS, Roland ULg; ACQUAVIVA, Cécile et al

Poster (2013, September)

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See detailIdentification of methylenecyclopropyl acetic acid in serum of European horses with atypical myopathy
Votion, Dominique ULg; van Galen, G; Sweetan et al

in Equine Veterinary Journal (2013)

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See detailEnhanced interpretation of newborn screening results without analyte cutoff values
Marquardt, G.; Currier, R.; McHugh, D. M. S. et al

in Genetics in Medicine (2012), 14(7), 648-655

Purpose: To improve quality of newborn screening by tandem mass spectrometry with a novel approach made possible by the collaboration of 154 laboratories in 49 countries. Methods: A database of 767,464 ... [more ▼]

Purpose: To improve quality of newborn screening by tandem mass spectrometry with a novel approach made possible by the collaboration of 154 laboratories in 49 countries. Methods: A database of 767,464 results from 12,721 cases affected with 60 conditions was used to build multivariate pattern recognition software that generates tools integrating multiple clinically significant results into a single score. This score is determined by the overlap between normal and disease ranges, penetration within the disease range, differences between conditions, and weighted correction factors. Results: Ninety tools target either a single condition or the differential diagnosis between multiple conditions. Scores are expressed as the percentile rank among all cases with the same condition and are compared to interpretation guidelines. Retrospective evaluation of past cases suggests that these tools could have avoided at least half of 279 false-positive outcomes caused by carrier status for fatty-acid oxidation disorders and could have prevented 88% of known false-negative events. Conclusion: Application of this computational approach to raw data is independent from single analyte cutoff values. In Minnesota, the tools have been a major contributing factor to the sustained achievement of a false-positive rate below 0.1% and a positive predictive value above 60%. © 2012 American College of Medical Genetics and Genomics. [less ▲]

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See detailHepatocyte transplantation using the domino concept in a child with Tetrabiopterin non-responsive phenylketonuria.
Stephenne, X.; DEBRAY, François-Guillaume ULg; Smets, F. et al

in Cell Transplantation (2012), 21(12), 2765-70

Phenylketonuria is a metabolic disease caused by phenylalanine hydroxylase deficiency. Treatment is based on a strict natural protein-restricted diet that is associated with the risk of malnutrition and ... [more ▼]

Phenylketonuria is a metabolic disease caused by phenylalanine hydroxylase deficiency. Treatment is based on a strict natural protein-restricted diet that is associated with the risk of malnutrition and severe psychosocial burden. Oral administration of tetrahydrobiopterin can increase residual enzyme activity, but most patients with severe clinical phenotypes are non-responders. We performed liver cell transplantation in 6 years-old boy with severe tetrahydrobiopterin non-responsive phenylketonuria, who failed to comply with diet prescriptions. The transplanted hepatocytes were obtained in part from an explanted glycogen storage type 1b liver. Following two infusions, blood phenylalanine levels returned within the therapeutic target while the phenylalanine half-life assessed by loading tests decreased from 43 h to 19 h. However, three months later, blood phenylalanine concentrations increased and the phenylalanine intake had to be reduced. Cell based therapy is a promising therapeutic option in phenylketonuria and the domino concept may solve the issue of cell sources for hepatocyte transplantation. [less ▲]

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See detailNeonatal thyroid-stimulating hormone concentrations in Belgium: a useful indicator for detecting mild iodine deficiency?
Vandevijvere, S; Coucke, W; Vanderpas, J et al

in PLoS ONE (2012)

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See detailClinical validation of cutoff target ranges in newborn screening of metabolic disorders by tandem mass spectrometry: a worldwide collaborative project.
McHugh, David; Cameron, C. A.; Abdenur, J. E. et al

in Genetics in Medicine : Official Journal of the American College of Medical Genetics (2011), 13(3), 230-54

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See detail3-years experience review of neonatal screening for hemoglobin disorders using tandem mass spectrometry.
BOEMER, François ULg; Cornet, Yves ULg; LIBIOULLE, Cécile ULg et al

in Clinica Chimica Acta (2011), 412(15-16), 1476-9

BACKGROUND: Neonatal screening programs for sickle cell disease are common in North America and in some European countries. Isoelectric Focusing or High Performance Liquid Chromatography is the main ... [more ▼]

BACKGROUND: Neonatal screening programs for sickle cell disease are common in North America and in some European countries. Isoelectric Focusing or High Performance Liquid Chromatography is the main technique used for hemoglobin variant detection. METHODS: Since tandem mass spectrometry is being used for screening of inherited metabolic disorders and allows protein identification, we had developed an application to identify the most relevant hemoglobin mutations with this technology. RESULTS: This approach had been previously validated and has been routinely applied in our laboratory for the last three years. We report here our experience with this new method in the field, applied to our East-Belgian population. CONCLUSIONS: To conclude, mass spectrometry provides an efficient alternative approach for laboratories performing neonatal screening of hemoglobin disorders. [less ▲]

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See detailNewborn Screening for Sickle Cell Disease using Tandem Mass Spectrometry
BOEMER, François ULg

Conference (2009, April)

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See detailDépistage Néonatal de la Drépanocytose: Nouvelles Méthodologies
BOEMER, François ULg

Doctoral thesis (2009)

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See detailAnalytical validation based on total error measurement and cut-off interpretation of a neonatal screening TSH-immunoassay.
Boemer, François ULg; Bours, Vincent ULg; Schoos, Roland ULg et al

in Journal of Chromatography. B : Analytical Technologies in the Biomedical & Life Sciences (2009), 877

To prevent the severe developmental and physical morbidities associated with congenital hypothyroidism, we developed a home-made Enzyme-Linked Immunosorbent Assay (ELISA) method to quantify Thyroid ... [more ▼]

To prevent the severe developmental and physical morbidities associated with congenital hypothyroidism, we developed a home-made Enzyme-Linked Immunosorbent Assay (ELISA) method to quantify Thyroid Stimulating Hormone (TSH) levels on newborn dried blood spots. In order to agree with actual clinical laboratory quality referential (ISO 15189), we desired to update our analytical validation protocol. For this purpose, an approach using accuracy profiles based on tolerance intervals for the total error measurement was for first time applied to an immunological assay. According to acceptance limits fixed at +/-30%, the method was found accurate over a concentration range from 17.48 to 250mIU/L. Based on 99.5 percentile of a 16,459 newborn population, cut-off was fixed at 20.1mIU/L and validated against normal and pathologic neonatal populations. Additionally, uncertainty regions around this value were obtained applying four different approaches. Finally, we demonstrated here our in-house immunological technique fulfils criterions of a neonatal screening policy. [less ▲]

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See detailNewborn Screening for Sickle Cell Disease Using Tandem Mass Spectrometry
Boemer, François ULg; Ketelslegers, Olivier; Minon, Jean-Marc et al

in Clinical Chemistry (2008), 54(12), 2036-2041

BACKGROUND: Neonatal screening programs for sickle cell disease are now widespread in North American and European countries. Most programs apply isoelectric focusing or HPLC to detect hemoglobin variants ... [more ▼]

BACKGROUND: Neonatal screening programs for sickle cell disease are now widespread in North American and European countries. Most programs apply isoelectric focusing or HPLC to detect hemoglobin variants. Because tandem mass spectrometry (MS/MS) is being used for screening of inherited metabolic disorders and allows protein identification, it was worth testing for hemoglobinopathy screening. METHODS: We minimized sample preparation and analysis times by avoiding prior purification, derivatization, or separation. We developed a tryptic digestion methodology to screen for the main clinically important variants (HbS, HbC, and HbE) and beta-thalassemia. To ensure proper discrimination between homozygote and heterozygote variants, we selected 4 transitions with good signal intensities for each specific peptide and calculated variant/HbA ratios for each. Method validation included intra- and interseries variability, carryover, and limit of detection. We also performed a comparative study with isoelectric focusing results on 2082 specimens. RESULTS: Intraassay imprecision values (CVs) varied between 2.5% and 30.7%. Interassay CVs were between 6.3% and 23.6%. Carryover was <0.03%, and the limit of detection was fixed at 1% of HbS. According to the MS/MS settings (detection of HbS, HbC, HbE, and beta-globin production defects), the comparative study did not yield any discrepant results between the 2 techniques. CONCLUSIONS: MS/MS is a reliable method for hemoglobinopathy neonatal screening. [less ▲]

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See detailMolecular Analysis in Two Siblings African Patients with Severe Form of Hunter Syndrome: Identification of a Novel (P.Y54x) Nonsense Mutation
Mutesa, Léon; Muganga, N.; Lissens, Willy et al

in Journal of Tropical Pediatrics (2007), 53(6), 434-7

Hunter syndrome (or Mucopolysaccharidosis type II, MPS II) is an X-linked recessive disorder due to the deficiency of the iduronate-2-sulfatase (IDS) enzyme, resulting in the accumulation of heparan and ... [more ▼]

Hunter syndrome (or Mucopolysaccharidosis type II, MPS II) is an X-linked recessive disorder due to the deficiency of the iduronate-2-sulfatase (IDS) enzyme, resulting in the accumulation of heparan and dermatan sulfates in the lysosomes. The heterogeneity of clinical phenotypes, ranging from mild-to-severe forms, is a result of different mutations in the IDS gene. We report here, a novel nonsense mutation (p.Y54X) in two siblings MPS II African patients affected with a severe form of the disease. We postulated that the p.Y54X mutation which causes a loss of the IDS region highly conserved among sulfatase enzymes, could be predicted as a severe disease-causing mutation for Hunter syndrome. [less ▲]

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See detailNeonatal screening for sickle cell disease in Central Africa: a study of 1825 newborns with a new enzyme-linked immunosorbent assay test
Mutesa, Léon; Boemer, François ULg; Ngendahayo, Louis et al

in Journal of Medical Screening (2007), 14(3), 113-116

Objectives To evaluate the feasibility of systematic neonatal screening for sickle cell disease in the region of Great Lakes in Central Africa using a new approach with limited costs. Methods Between July ... [more ▼]

Objectives To evaluate the feasibility of systematic neonatal screening for sickle cell disease in the region of Great Lakes in Central Africa using a new approach with limited costs. Methods Between July 2004 and July 2006, 1825 newborn dried blood samples were collected onto filter papers in four maternity units from Burundi, Rwanda and the East of the Democratic Republic of Congo. We tested for the presence of haemoglobin C and S in the eluted blood by an enzyme-linked immunosorbent assay (ELISA) test using a monoclonal antibody. All ELISA-positive samples (multiple of the median (MoM) >= 1.5) were confirmed by a simple molecular test. The statistica software version 7.1 was used to create graphics and to fix the MoM cut-off, and the chi(2) of Pearson was used to compare the genotype incidences between countries. Results Of the 1825 samples screened, 97 (5.32%) were positive. Of these, 60 (3.28%) samples were heterozygous for Hb S, and four (0.22%) for Hb C; two (0.11%) newborns were Hb SS homozygotes. Conclusions The lower cost and the high specificity of ELISA test are appropriate for developing countries, and such systematic screening for sickle cell anaemia is therefore feasible. [less ▲]

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See detailNeonatal screening of hemoglobinopathies on dried blood
BOEMER, François ULg

Conference (2007)

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See detailScreening for sickle cell disease on dried blood: a new approach evaluated on 27,000 Belgian newborns
Boemer, François ULg; Vanbellinghen, Jean-François ULg; Bours, Vincent ULg et al

in Journal of Medical Screening (2006), 13(3), 132-136

Setting Early diagnosis of sickle cell disease decreases morbidity. However, cost-effective screening programmes are not yet available. Methods We explored the feasibility of systematic screening ... [more ▼]

Setting Early diagnosis of sickle cell disease decreases morbidity. However, cost-effective screening programmes are not yet available. Methods We explored the feasibility of systematic screening performed on dried blood harvested from five-day-old newborns. Results A total of 27,010 samples were collected in Belgian maternity units between June 2003 and February 2005, and the presence of haemoglobin (Hb) C or S in the eluted blood was examined by an enzyme-linked immunosorbent assay (ELISA) test performed with a monoclonal antibody detecting both mutated forms. As this antibody slightly cross-reacts with Hb A, better specificity is achieved if the test is performed not later than day 5. Among the 27,010 samples, 132 (0.49%) were positive. Molecular biology tests performed on dried blood from positive samples showed that 106 of these babies were heterozygotes for the Hb S mutation and three were heterozygotes for the Hb C mutation, while three newborns were SS homozygotes (0.011%). Seventeen samples (0.063%) were false-positives as we could not detect any mutation. Conclusions We have developed a new immunological approach in the field of haemoglobinopathy neonatal screening. This ELISA test is cheap (E0.2 /test or E1800/cletected SS homozygote) and could be centralized. Its cost-effectiveness in the whole Belgian population is comparable with that of screening for phenylketonuria or congenital adrenal hyperplasia. Further improvements should obviously be achieved in order to better discriminate heterozygotes and homozygotes, but the accessibility and the low cost of the test are relevant arguments for the screening extension in a wide range of countries, especially in Central Africa. [less ▲]

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