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Aim: Type 1 diabetes (T1D) and its complications are known to be associated with oxidative stress. Pteridine derivatives and indoleamine 2,3-dioxygenase (IDO) activity can be used as biomarkers in the evaluation of oxidative stress. In this study, our aim is to compare the concentrations of serum and urinary pteridine derivatives, as well as serum IDO activity, in children and adolescents diagnosed with T1D and those in a healthy control group., Method: A cross-sectional study was performed and included 93 patients with T1D and 71 healthy children. Serum and urine biopterin, neopterin, monapterin, pterin, isoxanthopterin, and pterin-6-carboxylic acid (6PTC) and serum tryptophan and kynurenine levels were analyzed and compared with healthy controls. High-performance liquid chromatography was used for the analysis of pteridine derivatives, tryptophan, and kynurenine. Xanthine oxidase (XO) activity, a marker of oxidative stress, was defined by measurement of serum and urine isoxanthopterin. As an indicator of indolamine 2,3-dioxygenase (IDO) activity, the ratio of serum kynurenine/tryptophan was used., Results: Serum isoxanthopterin and tryptophan concentrations were increased, and serum 6PTC concentration was decreased in children with T1D (p=0.01, p=0.021, p<0.001, respectively). In children with T1D, IDO activity was not different from healthy controls (p>0.05). Serum neopterin level and duration of diabetes were weakly correlated (p=0.045, r=0.209); urine neopterin/creatinine and isoxanthopterin/creatinine levels were weakly correlated with HbA1c levels (p=0.005, r=0.305; p=0.021, r=0.249, respectively). Urine pterin/creatinine level negatively correlated with body mass index-SDS. (p=0.015, r=-0.208)., Conclusion: We found for the first time that isoxanthopterin levels increased and 6PTC levels decreased in children and adolescents with T1D. Elevated isoxanthopterin levels suggest that the XO activity is increased in TID. Increased XO activity may be an indicator of vascular complications reflecting T1D-related endothelial dysfunction., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Fabry disease is characterized by the accumulation of globotriaosylceramide. Substrate accumulation in lysosomes is thought to trigger an inflammatory response and is responsible for progressive organ damage through the induction of autoimmunity. The levels of pteridine and kynurenine pathway metabolites increase when immune activation is observed and are employed to monitor several diseases and determine prognosis., Aims: To elucidate the effects of immune activation on the pathophysiology of Fabry disease and to investigate the potential utility of pteridine and kynurenine metabolites., Study Design: A prospective case-control study., Methods: In this study, 33 patients with Fabry disease and 33 age-and sex-matched healthy controls were included. Blood pteridine and kynurenine metabolites were studied in both groups. Organ involvement in Fabry disease and its correlation with the pteridine and kynurenine pathways were also investigated., Results: The patients’ neopterin and biopterin levels and the tryptophan/kynurenine ratio were statistically higher than those of the healthy control group ( p < 0.05). A statistically significant association was found between neopterin levels and hypertrophic cardiomyopathy, cardiac arrhythmias, and GFR values ( p = 0.044, p = 0.021, and p = 0.030, respectively), tryptophan and corneal verticillate, hearing loss and tinnitus ( p = 0.010, p = 0.009 and p = 0.046, respectively), and kynurenine levels and valvular heart disease ( p = 0.020)., Conclusion: From the onset of the disease, patients with Fabry disease exhibited elevated levels of inflammation and immune activation. Furthermore, inflammation and immune activation markers can be used as early disease biomarkers., Competing Interests: Conflict of Interest: No conflict of interest was declared by the authors.

Orotic aciduria is a severe, hereditary, life-threatening condition, particularly in newborns. An increased orotic acid (OA) content in urine may be a strong indicator of this condition. In this study, we developed a rapid, simple, highly sensitive diagnostic method for use in monitoring the OA levels in urine samples, which were successfully determined using capillary electrophoresis combined with capacitively coupled contactless conductivity detection (CE-C 4 D). A straightforward analysis with an increased sensitivity towards OA and an analysis time of approximately 5 min were realized, and the limit of detection of the developed method was 0.014 mg/L in aqueous solution. The optimized composition of the separation electrolyte was 20 mM 2-(N-morpholino)ethanesulfonic acid/histidine with 0.1 mM cetyltrimethylammonium bromide at a pH of 6.5. The sensitivity of the developed method was significantly increased using a sample stacking approach with a 10% acetonitrile (v/v) plug solution. The method was validated, and satisfactory recoveries of 80.0-92.3% were obtained. The amounts of OA in five urine samples were successfully determined., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Biotinidase deficiency (BD) is an autosomal recessive inherited disorder of biotin recycling that leads to neurological and cutaneous consequences if left untreated. The clinical features of BD can be ameliorated or prevented by the administration of pharmacological doses of the vitamin biotin. Since it is a treatable disorder, BD is included in the newborn screening program in Türkiye as in many other countries. Therefore, monitoring of biotinidase enzyme activity (BEA) is of vital importance, especially for patients. The aim of this study was to develop a simple and reliable colorimetric method based on digital imaging for the analysis of BEA in serum samples. To determine the optimum distance and LED light source in the analyzer box that we fabricated in the laboratory, images of the solutions in a 96-well microplate were taken with a mobile phone camera, and each color space was examined. The most reliable relationship was between blank subtracted intensities of green channel and analyte concentrations, which was in the range of 35-400 ng/mL p -aminobenzoic acid ( r 2 = 0.999). The limit of detection and limit of quantification were 11 and 35 ng/mL, respectively. The proposed method was successfully applied to serum samples of 60 patients with BD and 60 healthy controls. We claim that the method can be easily performed for determination of BEA anywhere without needing expensive instruments., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

2-hydroxyglutaric aciduria is an inherited neurometabolic disorder with two major types: D-2-hydroxyglutaric aciduria and L-2-hydroxyglutaric aciduria. An easy and fast capillary electrophoresis system combined with a capacitively coupled contactless conductivity detection method was developed for the enantioseparation and determination of D- and L-2-hydroxyglutaric acid in urine. D- and L-2-hydroxyglutaric acids were separated using vancomycin as the chiral selector. The optimal separation conditions for enantiomers were achieved by the use of a buffer containing 50 mM 4-(N-morpholino) butane sulfonic acid solution (pH 6.5), an electroosmotic flow modifier (0.001% [w/v] polybrene), and 30 mM vancomycin as chiral selector. The analysis time was 6 min under optimal conditions. The optimized and validated method was successfully implemented for quantifying D- and L-2-hydroxyglutaric aciduria in patients' urine, without any pretreatment step. The linearity of the method was determined to be in the range of 2-100 mg/L for D- and L-2-hydroxyglutaric acid in urine. The precision (relative standard deviation%) was obtained at about 7%. For D- and L-2-hydroxyglutaric acids, the limits of detection were 0.567 and 0.497 mg/L, respectively., (© 2023 Wiley-VCH GmbH.)

Objective: Pathologic results in expanded metabolic screening tests may be due to the medications, inappropriate sampling methods, or the maternal originated inborn errors of metabolism. The aim of this study is to identify mothers with inborn errors of metabolism through the pathologic expanded metabolic screening results of their babies., Materials and Methods: Babies who were under 1 year of age and had a pathologic result of an expanded newborn screening for inborn errors of metabolism and their mothers were included in this retrospective single-centered study. Data of expanded metabolic screening results of both babies and their mothers were recorded. Clinical and laboratory findings relevant to suspected inborn errors of metabolism due to the pathologic screening results analysis were also noted for the mothers., Results: Seventeen babies and their mothers were enrolled. Expanded metabolic screening results were found compatible with inborn errors of metabolism in 4 (23.5%) of 17 mothers. Two of these mothers were diagnosed with 3-methylcrotonyl-CoA carboxylase deficiency and 2 mothers were diagnosed with glutaric aciduria type 1., Conclusion: Inborn errors of metabolism can present in any period of life, and this is the first study to address the importance of metabolic screening via tandem mass spectrometry in terms of early diagnosis of inborn errors of metabolism not only in pediatric aged patients but also in adulthood in Turkey. The performance of expanded metabolic screening tests may be an important step in terms of detecting maternal inborn errors of metabolism that are not diagnosed until adulthood.

Background: Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood and manifests mainly as autoinflammation of the joints and other tissues. Several treatment options such as nonsteroidal antiinflammatory drugs, methotrexate, and intra-articular steroids are widely used to relieve and improve this inflammation. Secondary carnitine deficiency can be detected in chronic diseases by either renal loss or increased demand. While carnitine status can be associated with several conditions, in the present study our aim is to determine the levels of free carnitine and acyl-carnitine in Turkish JIA patients., Methods: One hundred and fourteen patients diagnosed with juvenile idiopathic arthritis and 50 healthy individuals who served as the control group were included in the study. A fasting blood sample was collected from the children in both groups to determine free carnitine and acylcarnitine ester by quadripole electrospray tandem mass spectrometry (ESI-MS/ MS)., Results: Screening of acyl-carnitine profile revealed free carnitine, C14, C14:2, C16, C16-OH, and C18 carnitine levels were higher (p < 0.0001, p < 0.0001, p < 0.001, p < 0.001, and p = 0.011, respectively), while C2, C3, C4, C6, C8, C10, C10:1, C10:2, C3DC, C4DC, C5DC, C4-OH, and C18:1-OH carnitine levels were lower (p < 0.0001) in JIA patients in comparison to the control group. Total acyl-carnitine levels (p < 0.001) and acyl-carnitine to free carnitine ratio (p < 0.001) were also lower in JIA patients than the control group. Free carnitine levels were significantly higher (48.05 ± 13.36 μmol/L) in patients under antiinflammatory drug therapy than those who did not receive any treatment (43.18 ± 7.96 μmol/L) (p = 0.004)., Discussion: In the present study we were not able to define secondary carnitine deficiency in JIA patients, although free carnitine and acyl-carnitine variations were detected in JIA patients. In conclusion, routine carnitine supplementation is not recommended in all patients with JIA.

Aim: L-2-hydroxyglutaric aciduria is a slowly progressive neurometabolic disorder caused by an enzymatic deficiency of L-2-hydroxyglutarate dehydrogenase. Here, we aimed to evaluate the clinical, neuroradiologic, and genotypic characteristics of patients with L-2-hydroxyglutaric aciduria who were followed in our outpatient clinic., Material and Methods: Twenty-five patients with L-2-hydroxyglutaric aciduria were enrolled in the study. Data regarding demographic, clinical, and neuroradiologic findings and molecular analysis were evaluated retrospectively., Results: The mean age of patients at the time of diagnosis was 12.09±8.02 years, whereas the mean age at the time of the first symptoms was 39.47±29.96 months. Diagnostic delay was found as 9.95±7.78 years. Developmental delay, decrease in school success, and seizures were the most common initial symptoms; however, behavioral problems and seizures became more prominent in the disease course. At the time of diagnosis, mental retardation and at least one pathologic cerebellar finding were detected in all symptomatic patients. Three patients developed brain tumors. The most common neuroimaging findings were subcortical white matter changes and cerebellar dentate nucleus involvement. In one patient, there was only isolated basal ganglia involvement without white matter lesions. Patients with similar genotypic features exhibited different clinical and radiologic findings., Conclusion: Although clinical symptoms appear early in L-2-hydroxyglutaric aciduria, there is approximately a ten-year delay in diagnosis. In subjects in whom brain tumor is detected in early childhood, L-2-hydroxyglutaric aciduria should be considered in the differential diagnosis in the presence of mental retardation accompanied by developmental delay, cerebellar and pyramidal findings, and behavior disorders in a wide spectrum ranging from autism spectrum disorder to psychosis. In patients with L-2-hydroxyglutaric aciduria, incipient headache, tinnitus, altered consciousness, and seizures can be indicative of brain tumors., Competing Interests: Conflict of Interest: The authors have no conflicts of interest to declare., (Copyright: © 2020 Turkish Archives of Pediatrics.)

Ethylmalonic acid is a metabolic organic acid, and its accumulation in urine is diagnostic of ethylmalonic aciduria. In this study, a simple and fast method employing capillary electrophoresis equipped with capacitively coupled contactless conductivity detection was developed for the detection of ethylmalonic acid in urine samples. The optimized electrophoretic separation was performed in 50 mmol/L 2-(N-morpholino)ethanesulfonic acid solution, buffered at a pH of 6.5, and contained 0.13 mmol/L cetyltrimethylammonium bromide as an electroosmotic modifier. Electrophoresis was run at 28 kV in reversed polarity. The linear range of ethylmalonic acid concentration was between 1 and 100 mg/L with a regression coefficient of 0.9998. This method had good intra- and interday precision with <5% relative standard deviations. The detection limit (signal-to-noise ratio = 3) and the quantification limit (signal-to-noise ratio = 10) values were 0.139 and 0.466 mg/L, respectively. Using our optimized conditions, the method was successfully employed for the detection of ethylmalonic acid in urine sample of ethylmalonic aciduria patient., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Objectives: This study aims to determine the prevalence of Fabry disease (FD) among patients with juvenile systemic lupus erythematosus (SLE)., Patients and Methods: This cross-sectional study included 76 juvenile SLE patients (12 males; 64 females; mean age 16±3.3 years; range, 8 to 23.5 years) who were diagnosed according to 1997 update of the 1982 American College of Rheumatology revised criteria for classification of SLE. Since the majority of patients were female, alpha-galactosidase A gene was investigated for mutations resulting in FD. Lysosomal accumulation of globotriaosylsphingosine (lyso-Gb3) was further evaluated in mutation positive subjects by using dried blood spot testing., Results: Alpha-galactosidase A gene screening did not yield any positive mutation in our 74 subjects. However, a heterozygous p.D313Y mutation was found in two females. These subjects were further investigated for lyso-Gb3 levels in dried blood spot samples and the levels of lyso-Gb3 being normal lead to exclusion of FD in these two patients., Conclusion: We do not suggest routine screening of FD in patients with juvenile SLE; however, prospective studies with larger sample sizes are needed for further analysis., Competing Interests: Conflict of Interest: The authors declared no conflicts of interest with respect to the authorship and/or publication of this article., (Copyright © 2020, Turkish League Against Rheumatism.)

Aim: The primary purpose of the present study is to evaluate the effect of chenodeoxycholic acid treatment on skeletal system findings in patients with cerebrotendinous xanthomatosis., Material and Methods: This retrospective study was conducted between June 2013 and December 2018 with seven patients with cerebrotendinous xanthomatosis in Cerrahpasa Medical Faculty Pediatric Nutrition and Metabolism Department. The clinical, epidemiologic, and genotypic features of the patients were reviewed in detail and the following items, especially related with skeletal system involvement, were recorded from medical data: history of a bone fracture, plasma calcium, phosphate, alkaline phosphatase and 25-hydroxy-vitamin D concentrations, bone mineral density values of the posteroanterior lumbar spine (L1-L4), and femoral neck before and after chenodeoxycholic acid treatment., Results: Regarding the bone mineral metabolism, plasma calcium, phosphate, alkaline phosphatase levels were found in normal ranges in all patients. Plasma 25-hydroxy-vitamin D evaluation at the time of diagnosis showed deficiency in three patients and insufficiency in three patients. Following chenodeoxycholic acid therapy, 25-hydroxy-vitamin D deficiency persisted in only one patient, but insufficiency was observed in four patients. According to the bone mineral density assessments, four patients had Z-scores below the expected range for age both at initial examination and after chenodeoxycholic acid therapy. No significant difference was observed between plasma 25-hydroxy-vitamin D levels and bone mineral density Z-scores before or after treatment., Conclusion: This study elucidates the necessity of additional medical treatment as a part of chenodeoxycholic acid therapy to improve skeletal system findings in cerebrotendinous xanthomatosis., Competing Interests: Conflict of Interest: The authors have no conflicts of interest to declare.

Excess urinary orotic acid excretion occurs in patients with some inborn errors of metabolic pathways such as pyrimidine synthesis and urea cycle. Thus, rapid diagnosis of orotic aciduria has a vital importance for patients. In this paper, a novel method for determination of orotic acid in urine samples by ion chromatography with suppressed conductivity detection was investigated. The separation of orotic acid from urine matrix was accomplished by using an anion exchange column with optimized isocratic eluent program which utilized 50 mM NaOH. The other chromatographic conditions were as follows: the suppressor current was 31 mA; the flow rate of mobile phase was 0.25 mL min -1 ; the column temperature was 30 °C; sample loop volume was 10 μL. Under optimized conditions, the limit of detection was 0.2 μmol L‾ 1 . Dramatically elevated orotic acid concentration was observed on pathological urine samples comparing to healthy urines, as expected. There are a good many advantages of the proposed method, but using an environmentally friendly reagent free system, no organic solvent employment and its quick nature, and being a sensitive and reliable method are the most obvious ones. The proposed method, therefore, may be utilized as an alternative technique for clinical laboratories., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Homogentisic acid (HGA) is a diagnostic metabolite that accumulates in the urine and tissues of patients with alkaptonuria which is a rare autosomal recessive disease. HGA is a specific metabolite in urine and serum, which is used for diagnosis of alkaptonuria. This study presents an inexpensive and easy capillary electrophoretic method for the quantitative determination of HGA in urine samples. The method was optimized using full factorial experimental design. The optimal separation electrolyte and separation voltage were revealed as 45 mmol/L phosphate buffer at pH 7.0 and 22 kV, respectively. Under these conditions the presence of HGA was detected in 6 min. Repeatability of migration times and corrected peak areas of HGA (as RSD) were 0.37 and 1.99, respectively. The detection limit was 0.56 μg/mL, 3 times of the average noise, and the quantification limit was 1.85 μg/mL, 10 times the average noise for HGA. Urine samples were directly injected to the capillary without any pretreatment step., (Copyright © 2018 John Wiley & Sons, Ltd.)

Objectives: This study aims to demonstrate the patterns of free carnitine (FC) and acylcarnitine (AC) esters in familial Mediterranean fever (FMF) patients., Patients and Methods: A total of 205 patients (106 males, 99 females; mean age 131.3±52.1 months; range 24 to 254 months) with FMF and 50 healthy controls (27 males, 23 females; mean age 125.7±49.6 months; range 32 to 217 months) were enrolled. Fasting dried blood samples were taken for showing FC and AC ester levels with tandem mass spectrometry from both patients and controls., Results: Screening of AC profile revealed increased FC, 3-hydroxypalmitoylcarnitine (C16-OH), and 3-Hydroxy octadecanoylcarnitine (C18:2-OH) carnitine levels, while decreased acetyl-carnitine (C2), propionyl-carnitine (C3), butyryl-carnitine (C4), tiglyl-carnitine (C5:1), hexanoyl-carnitine (C6), octanoyl-carnitine (C8), decenoylcarnitine (C10:1), decadienoylcarnitine (C10:2), malonylcarnitine (C3DC), methylmalonylcarnitine (C4DC), glutarylcarnitine (C5DC), hexadecenoylcarnitine (C16:1), 3-Hydroxy butyrylcarnitine (C4-OH), and 3-Hydroxy oleylcarnitine (C18:1-OH) carnitine levels in FMF patients compared to controls. Total AC levels (p<0.001) and AC to FC ratio (p<0.001) were also lower in FMF patients than the controls., Conclusion: In this study, we were able to detect some of the AC profile variations in FMF patients; however, usage of carnitine in all patients with FMF is not recommended since we were not able to demonstrate secondary carnitine deficiency in FMF patients of this study., Competing Interests: Conflict of Interest: The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.