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Abstract: Introduction: Infant vitamin B12 deficiency can manifest as a severe neurodegenerative disorder and is usually caused by maternal deficiency due to vegetarian diet or pernicious anaemia. Its early recognition and treatment can prevent potentially serious and irreversible neurologic damage. Biochemically, vitamin B12 deficiency leads to an accumulation of methylmalonic acid, homocysteine, and propionylcarnitine. Expanded newborn screening using tandem mass spectrometry may identify neonatal and maternal vitamin B12 deficiency by measurement of propionylcarnitine and other metabolites in the dried blood spot sample of newborns. Aim: To summarize our experiences gained by screening for vitamin B12 deficiency. Method: Clinical and laboratory data of vitamin B12-deficient infants diagnosed in Szeged Screening Centre were retrospectively analysed. Results: In Hungary, expanded newborn screening was introduced in 2007. Since then approximately 395 000 newborns were screened in our centre and among them, we identified four newborns with vitamin B12 deficiency based on their screening results. In three cases an elevated propionylcarnitine level and in the fourth one a low methionine level were indicative of vitamin B12 deficiency. We also detected an additional vitamin B12-deficient infant with neurological symptoms at 4 months of age, after a normal newborn screening, because of elevated urinary methylmalonic acid concentration. Vitamin B12 deficiency was secondary to maternal autoimmune pernicious anaemia in all the five infants. As a result of the recognized cases the incidence of infant vitamin B12 deficiency in the East-Hungarian region was 1.26/100 000 births, but the real frequency may be higher. Conslusions: Optimizing the cut off values of current screening parameters and measuring of methylmalonic acid and/or homocysteine in the dried blood spot, as a second tier test, can improve recognition rate of vitamin B12 deficiency. Orv Hetil. 2017; 158(48): 1909–1918.

Simultaneous determination of kynurenines, neurotransmitters, pterins and steroids linked to various neurological and metabolic diseases have important diagnostic significance for related pathology and drug monitoring. An improved, sensitive and selective ultra-high performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometric (UHPLC-MS/MS) method, based on our earlier publication, has been proposed for the quantitative measurement of 42 metabolites in human urine. The assay covers a larger number of analytes, uses an advanced, Waters Atlantis T3 chromatographic column and similarly meets the guideline of European Medicines Agency (EMA) on bioanalytical method validation. Analytical performance met all the EMA requirements and the assay covered the relevant clinical concentrations. Linear correlation coefficients were all > 0.998. Intra-day and inter-day accuracy and precision were 87−118%, 81−120% and 2–20%, respectively including the lower limit of quantification (LLOQ). The assay is expected to facilitate the diagnosis and allows drug level monitoring from urine.

Concurrent measurement of tyrosine, tryptophan and their metabolites, and other co-factors could help to diagnose and better understand a wide range of metabolic and neurological disorders. The two metabolic pathways are closely related to each other through co-factors, regulator molecules and enzymes. By using high performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometry, we present a robust, selective and comprehensive method to determine 30 molecules within 20 min using a Waters Atlantis dC18. The method was validated according to the guideline of European Medicines Agency on bioanalytical method validation. Analytical performance met all the EMA requirements and the assay covered the relevant clinical concentrations. Linear correlation coefficients were all >0.998. Intra-day and inter-day accuracy were between 80-119% and 81-117%, precision 1-19% respectively. The method was applied to measure TYR, TRP and their metabolites, and other neurologically important molecules in human serum and CSF samples. The assay can facilitate the diagnosis and is suitable for determination of reference values in clinical laboratories.

Congenital adrenal hyperplasia (CAH) is a severe inherited disorder of cortisol biosynthesis that is potentially lethal or can seriously affect quality of life. For the first time, we aimed to assess the stability of 21-deoxycortisol (21Deox), 11-deoxycortisol (11Deox), 4-androstenedione (4AD), 17-hydroxyprogesterone (17OHP) and cortisol (Cort), diagnostic for CAH, in dried blood spots (DBSs) during a 1 year storage at different temperatures. Spiked DBS samples were stored at room temperature, 4 °C, -20 °C or -70 °C, respectively and analyzed in triplicates using liquid chromatography–tandem mass spectrometry at Weeks 0, 1, 2, 3 and 4, Month 6 and Year 1. Analyte levels within ±15% vs the baseline were considered stable. Our observations show that 21Deox, 4AD and 17OHP were not significantly changed for 1 year even at room temperature at either analyte levels. In contrast, Cort required storage at 4 °C, -20 °C or -70 °C for long-term stability, being significantly decreased at room temperature from Month 6 (p

Infant vitamin BTo summarize our experiences gained by screening for vitamin BClinical and laboratory data of vitamin BIn Hungary, expanded newborn screening was introduced in 2007. Since then approximately 395 000 newborns were screened in our centre and among them, we identified four newborns with vitamin B

The relationship between renal disease progression and genetic polymorphism of enzymes influencing endothelial function remains incompletely understood. We genotyped three cohorts of elderly Hungarian patients: 245 patients with end-stage renal disease (ESRD) on chronic hemodialysis (HD), 88 patients with mild chronic kidney disease (CKD), and 200 healthy controls. The underlying diagnoses of renal diseases were primary glomerulonephritis, interstitial nephritis, hypertension, diabetic nephropathy, and hereditary diseases. We examined genetic polymorphisms of eight candidate genes associated with endothelial function: endothelial constitutive nitric oxide synthase (ecNOS) T-786C, endothelin-1 G5727T, methylenetetrahydrofolate reductase (MTHFR) C677T, paraoxonase-1 Q192R and M55L, angiotensinogen M235T, angiotensin-converting enzyme (ACE) I/D and angiotensin II type 1 receptor A1166C gene. Six gene polymorphisms were detected by real-time polymerase chain reaction with melting-point analysis, and two via allele-specific amplification and gel electrophoresis. Control group patients were in Hardy-Weinberg equilibrium for all tested genotypes. In ESRD patients attributed to hypertension, the endothelin gene G5727T GG genotype occurred significantly less but GT genotype more frequently (P < 0.01 for both). In ESRD patients attributed to primary glomerulonephritis, more ACE DD and less ID genotypes were found (P < 0.02 for both) than in the controls. The underlying diagnosis may modify the association of genetic polymorphism and dialysis-dependent ESRD.

Background/Aims: Blood pressure (BP) during childhood is an established predictor of adult BP, which in turn predicts mortality in the event of cardiovascular disease. Reference data for systolic (SBP) and diastolic (DBP) BP are not available for Hungarian children (aged 11–14 years). The aim was to make up for this deficit. Methods: Analyses were performed on 14,504 Hungarian children aged 11–16 years. All measurements were made with a validated, automated device. Criteria described by international guidelines were used. Results: The 50th, 90th and 95th percentile BP values were defined by dividing the participating population into age-, gender- and height-specific subgroups. The SBP increased linearly with age to an apparent plateau at around the age of 15–16 years in both girls and boys, and there were similar increases in DBP and mean arterial pressure. Both the SBP and DBP revealed highly significant correlations in both genders with weight (SBP: r = 0.452, p < 0.01; DBP: r = 0.340, p < 0.01), height (SBP: r = 0.314, p < 0.01; DBP: r = 0.245, p < 0.01) and body mass index (SBP: r = 0.407, p < 0.01; DBP: r = 0.294, p < 0.01). Conclusion:The present study provides reference data on SBP and DBP, facilitating the diagnosis of essential hypertension in the 11- to 16-year age group.

Obesity-induced hypertension and essential hypertension in lean patients are two different forms of hypertension. The main goal of this study was to test whether there are differences in biochemical parameters between subjects with obesity-associated hypertension and those with essential hypertension. We examined whether the biochemical responses to angiotensin-converting enzyme inhibitor (ACEI) ramipril therapy reveal properties of these two conditions that might explain the differences in clinical outcome. Before ramipril therapy, the hypertensive group exhibited increases in ACE activity (p

Background/Aims: Paraoxonase 1 (PON1) is associated with high-density lipoproteins in the plasma, and is capable of hydrolysing oxidized lipids and preventing the oxidation of low-density lipoproteins. Oxidative stress and the PON1 (activity and Q192R polymorphism) were analysed in adolescent patients with essential (n = 49) or obesity-induced hypertension (n = 79), uraemic patients (n = 20), and also in obese normotensive patients (n = 60) and age-matched controls (n = 57). Methods: The PON1 activity was measured via paraoxon hydrolysis. The PON1 genotype was determined by real-time PCR. The levels of oxidized and reduced glutathione, the end-products of nitric oxide, cysteine, homocysteine and lipid peroxidation in the plasma were measured and related to the PON1 status. Results: There were no significant differences between the patient groups and the control group in the genotype distributions and the allele frequencies of the Q192R polymorphism. The PON activity was significantly lower (p < 0.001) in the uraemic hypertensive group than in the controls. The MDA concentration was significantly higher in the uraemic hypertensive (p < 0.001) and obese hypertensive (p < 0.05) patients. The plasma NOx concentrations were significantly lower (p < 0.001) and the ratio MDA/NOx were significantly higher in all four patient groups. The GSH levels were significantly lower in the patients with hypertension (p < 0.001) and obesity-induced hypertension (p < 0.05) than in the controls, while the GSSG level (p < 0.01) and the ratio GSSG/GSH (p < 0.05) was significantly higher in the uraemic hypertensive group. The plasma homocysteine level was significantly higher (p < 0.001) in the uraemic hypertensive patients as compared with the controls. Conclusions: We found no significant correlation between the biochemical parameters and neither genotypes nor enzyme activities. The PON1 status and the levels of certain biochemical parameters are independently associated with the hypertension in hypertensive and obese hypertensive patients, and the elevated levels of lipid peroxides and plasma homocysteine may contribute to the increased risk of cardiovascular complications in patients on haemodialysis.

A collaboration among 157 newborn screening programs in 47 countries has lead to the creation of a database of 705,333 discrete analyte concentrations from 11,462 cases affected with 57 metabolic disorders, and from 631 heterozygotes for 12 conditions. This evidence was first applied to establish disease ranges for amino acids and acylcarnitines, and clinically validate 114 cutoff target ranges. Objective: To improve quality and performance with an evidence-based approach, multivariate pattern recognition software has been developed to aid in the interpretation of complex analyte profiles. The software generates tools that convert multiple clinically significant results into a single numerical score based on overlap between normal and disease ranges, penetration within the disease range, differences between specific conditions, and weighted correction factors. Design: Eighty-five on-line tools target either a single condition or the differential diagnosis between two or more conditions. Scores are expressed as a numerical value and as the percentile rank among all cases with the condition chosen as primary target, and are compared to interpretation guidelines. Tools are updated automatically after any new data submission (2009- 2011: 5.2 new cases added per day on average). Main outcome measures: Retrospective evaluation of past cases suggest that these tools could have avoided at least half of 277 false positive outcomes caused by carrier status for fatty acid oxidation disorders, and could have prevented 88% of false negative events caused by cutoff 7 values set inappropriately. In Minnesota, their prospective application has been a major contributing factor to the sustained achievement of a false positive rate below 0.1% and a positive predictive value above 60%. Conclusions: Application of this computational approach to raw data could make cutoff values for single analytes effectively obsolete. This paradigm is not limited to newborn screening and is applicable to the interpretation of diverse multi-analyte profiles utilized in laboratory medicine. Abstract word

Apolipoprotein A5 (APOA5) gene variants have been shown to be associated with elevated TG levels; the T-1131C (rs662799) variant has been reported to confer risk for the metabolic syndrome in adult populations. Little is known about the APOA5 variants in pediatric population, no such information is available for pediatric obesity at all. Here we examined four haplotype-tagging polymorphisms (T-1131C, IVS3 + G476A [rs2072560], T1259C [rs2266788] and C56G [rs3135506]) and studied also the frequency of major naturally occurring haplotypes of APOA5 in obese children.The polymorphisms were analyzed in 232 obese children, and in 137 healthy, normal weight controls, using PCR-RFLP methods.In the pediatric patients we could confirm the already known adult subjects based association of -1131C, IVS3 + 476A and 1259C variants with elevated triglyceride concentrations, both in obese patients and in the controls. The prevalence of the APOA5*2 haplotype (containing the minor allele of T-1131C, IVS3 + G476A and T1259C SNPs together) was 15.5% in obese children, and 5.80% in the controls (p0.001); multiple logistic regression analysis revealed that this haplotype confers susceptibility for development of obesity (OR=2.87; 95% CI: 1.29-6.37; p≤0.01). By contrast, the APOA5*4 haplotype (with -1131C alone) did not show similar associations. Our findings also suggest that the APOA5*5 haplotype (1259C alone) can be protective against obesity (OR=0.25; 95% CI: 0.07-0.80; p0.05).While previous studies in adults demonstrated, that the APOA5 -1131C minor allele confers risk for adult metabolic syndrome, here we show, that the susceptibility nature of this SNP restricted to the APOA5*2 haplotype in pediatric obese subjects.

The microvascular responses to endothelium-dependent vasodilators (e.g., acetylcholine), endothelium-independent vasodilators (e.g., sodium nitroprusside), and to local heating were studied (for the first time) in adolescents with essential hypertension, grouped according to their body mass index. The forearm microvascular reactivities of thirty-three hypertensive adolescents (ten lean, 13 overweight, and ten obese) and 19 healthy controls were assessed by means of laser Doppler flowmetry. Blood levels of enzymatic and nonenzymatic antioxidants and malondialdehyde were determined. The perfusion increments in response to acetylcholine iontophoresis were not significantly attenuated in the patient groups as compared with the controls. Sodium nitroprusside (SNP) iontophoresis resulted in significantly smaller perfusion increments in the lean and obese hypertensives than in the controls (both p

Aims: This study comprised part of a larger cross-sectional survey performed in Hungary in the period 2005–2006, which was designed first to reveal the representative age-, gender- and height-specific percentile values for the systolic blood pressure (SBP) and the diastolic blood pressure (DBP) in Hungarian children aged 11–16 years. The second aim was to determine the prevalence of overweight and obesity. Methods: Analyses were performed on 14 290 Hungarian children aged 11–16 years. All blood pressure (BP) measurements were made with a validated, automated, digital device. The criteria recommended by international guidelines were used. Results: The prevalence of overweight and obesity among the Hungarian children was found to be 23.4% (3347 adolescents; International Obesity Task Force criteria). Previous studies have reported that the strongest correlation is observed between the BP values and weight, and our results are in accordance with this. Conclusions: Regional differences in morphometry (different prevalences of overweight and obesity) and the genetic background, disparate eating habits and other cultural factors may account for the differences in BP levels during childhood. As the prevalence of overweight and obesity is increasing worldwide, it is important that countries carefully monitor the weight and BP status of their children and adolescents.

Hypertension is an increasing public health problem all over the world. Essential hypertension accounts for more than 90% of cases of hypertension. It is a complex genetic, environmental and demographic trait. New method in molecular biology has been proposed a number of candidate genes, but the linkage or association with hypertension has been problematic (lack of gene-gene and gene-environment interaction). It is well known that genetic influences are more important in younger hypertensives, because children are relatively free from the common environmental factors contributing to essential hypertension. The association studies compare genotype ferquencies of the candidate gene between patient groups and the controls, in pathways known to be involved in blood pressure regulation. This study examined three polymorphisms of these factors encoding genes (ET-1 G+5665T (Lys198Asn), endothelial nitric oxide synthase (eNOS) T-786C promoter polymorphism and 27-bp repeat polymorphism in intron 4) in adolescents with juvenile essential and obesity-associated hypertension. Significant differences were found in the G/T genotype of the ET-1 polymorphism in the hypertensive and obese+hypertensive patients (body mass index (BMI)>30). A strong association was detected between the BMI and the polymorphism of the ET-1 gene. It seems that ET-1 gene polymorphism plays a role in the development of juvenile hypertension associated with obesity. Although no significant differences were seen in the case of the eNOS promoter polymorphism and the eNOS 4 th intron 27-bp repeat polymorphism. It seems that eNOS may play a role, but this is not the main factor in the control of blood pressure; it is rather a fine regulator in this process. This study with adolescents facilitates an understanding of the genetic factors promoting juvenile hypertension and obesity.

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.