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Background Enterovirus-A71 causes outbreaks of brainstem encephalitis, ranging from self-limited disease to acute flaccid paralysis. The aim of this study was to assess the role of cerebrospinal fluid (CSF) neopterin as a biomarker of disease severity in children with enterovirus-related brainstem encephalitis. Methods A descriptive, prospective cohort study was conducted from April 2016 to March 2017 in a tertiary hospital. Pediatric patients with a diagnosis of brainstem encephalitis with or without myelitis due to enterovirus infection were enrolled. The final study group comprised a convenience sample including all patients with sufficient CSF volume for neopterin determination. The major variables considered in estimating the severity were the diagnosis of encephalomyelitis, the presence of lesions and extensive lesions on brain and spinal magnetic resonance imaging (MRI), hospital stay length greater than seven days, and sequelae at day 30. Results Of 60 patients, CSF neopterin could be measured in 36. Median age was 26 months (interquartile range: 19 to 32). Thirty-three were diagnosed with brainstem encephalitis and three with encephalomyelitis. Enterovirus-A71 was the only identified genotype (25 of 25). CSF neopterin levels were elevated (>61 nmol/L) in 33 of 36 (92%), with a median of 347 nmol/L (interquartile range: 204 to 525). CSF neopterin was useful to distinguish patients with lesions on MRI (area under the receiver operating characteristic curve = 0.76; P = 0.02) and extensive lesions (area under the receiver operating characteristic curve = 0.76; P = 0.04). Conclusions This study suggests an association between CSF neopterin levels and the presence of inflammatory lesions on MRI.

BACKGROUND: Genetic defects of monoamine neurotransmitters are rare neurological diseases amenable to treatment with variable response. They are major causes of early parkinsonism and other spectrum of movement disorders including dopa-responsive dystonia. OBJECTIVES: The objective of this study was to conduct proteomic studies in cerebrospinal fluid (CSF) samples of patients with monoamine defects to detect biomarkers involved in pathophysiology, clinical phenotypes, and treatment response. METHODS: A total of 90 patients from diverse centers of the International Working Group on Neurotransmitter Related Disorders were included in the study (37 untreated before CSF collection, 48 treated and 5 unknown at the collection time). Clinical and molecular metadata were related to the protein abundances in the CSF. RESULTS: Concentrations of 4 proteins were significantly altered, detected by mass spectrometry, and confirmed by immunoassays. First, decreased levels of apolipoprotein D were found in severe cases of aromatic L-amino acid decarboxylase deficiency. Second, low levels of apolipoprotein H were observed in patients with the severe phenotype of tyrosine hydroxylase deficiency, whereas increased concentrations of oligodendrocyte myelin glycoprotein were found in the same subset of patients with tyrosine hydroxylase deficiency. Third, decreased levels of collagen6A3 were observed in treated patients with tetrahydrobiopterin deficiency. CONCLUSION: This study with the largest cohort of patients with monoamine defects studied so far reports the proteomic characterization of CSF and identifies 4 novel biomarkers that bring new insights into the consequences of early dopaminergic deprivation in the developing brain. They open new possibilities to understand their role in the pathophysiology of these disorders, and they may serve as potential predictors of disease severity and therapies. © 2020 International Parkinson and Movement Disorder Society.

Aim Gamma-aminobutyric acid (GABA) is a major modulator in brain maturation and its role in many different neurodevelopmental disorders has been widely reported. Although the involvement of GABA in different disorders has been related to its regulatory function as an inhibitory neurotransmitter in the mature brain, co-transmitter, and signalling molecule, little is known about its role as a clinical biomarker in neuropaediatric disorders. The aim of this study is to report the cerebrospinal fluid (CSF) free-GABA concentrations in a large cohort of patients (n=85) with different neurological disorders. Method GABA was measured in the CSF of neuropaediatric patients using capillary electrophoresis with laser-induced fluorescence detection. Other neurotransmitters (amino acids and monoamines) were also analysed. Results GABA concentrations in CSF were abnormal, with a greater frequency (44%) than monoamines (20%) in neuropaediatric patients compared with our reference values. Although we included a few patients with inborn errors of metabolism, GABA levels in CSF were more frequently abnormal in metabolic disorders than in other nosological groups. Interpretation Our work suggests further research into brain GABAergic status in neuropaediatric disorders, which could also lead to new therapeutic strategies. What this paper adds Homeostasis of GABA seems more vulnerable than that of monoamines in the developing brain. The highest GABA levels are found in the primary GABA neurotransmitter disorder SSADH deficiency. GABA alterations are not specific for any clinical or neuroimaging presentation.

The presence of monoamines and their cofactors (the pterins and vitamin B6 (pyridoxal phosphate (PLP))) in human cerebrospinal fluid (CSF) can be used as indicators of the biosynthesis and turnover of dopamine and serotonin in the brain. In addition, abnormalities in the CSF levels of these molecules are associated with various neurological diseases, including genetic diseases leading to dopamine and serotonin deficiency. Here, we provide a set of quantitative high-performance liquid-chromatography (HPLC) approaches to determine CSF levels of monoamines and their cofactors. This protocol describes step-by-step procedures for CSF sample preparation for the analysis of different molecules, HPLC calibration and analysis, and data quantification and interpretation. Unlike plasma/tissue/blood samples, CSF requires minimal sample preparation: in this protocol, only the analysis of PLP requires mixing with trichloroacetic acid to release the protein-bound vitamin, centrifugation, and mixing of the supernatant with phosphate buffer and sodium cyanide for derivatization in alkaline conditions. Monoamines are analyzed by HPLC with coulometric electrochemical detection (ED), pterins are analyzed by HPLC with coupled coulometric electrochemical and fluorescence detection, and PLP is analyzed by HPLC with fluorescence detection. The quantification of all compounds is achieved by external calibration procedures, and internal quality control and standards are analyzed in each run. We anticipate that investigation of dopamine and serotonin disturbances will be facilitated by measurements of these compounds in human CSF and other biological samples. The estimated time for the different procedures primarily depends on the electrochemical detector stabilization. Overnight stabilization of this detector is advised, and, after that step, preanalytical equilibration rarely exceeds 3 h.

The elevation of neopterin in cerebrospinal fluid (CSF) has been reported in several neuroinflammatory disorders. However, it is not expected that neopterin alone can discriminate among different neuroinflammatory etiologies. We conducted an observational retrospective and case–control study to analyze the CSF biomarkers neopterin, total proteins, and leukocytes in a large cohort of pediatric patients with neuroinflammatory disorders. CSF samples from 277 subjects were included and classified into four groups: Viral meningoencephalitis, bacterial meningitis, acquired immune-mediated disorders, and patients with no-immune diseases (control group). CSF neopterin was analyzed with high-performance liquid chromatography. Microbiological diagnosis included bacterial CSF cultures and several specific real-time polymerase chain reactions. Molecular testing for multiple respiratory pathogens was also included. Antibodies against neuronal and glial proteins were tested. Canonical discriminant analysis of the three biomarkers was conducted to establish the best discriminant functions for the classification of the different clinical groups. Model validation was done by biomarker analyses in a new cohort of 95 pediatric patients. CSF neopterin displayed the highest values in the viral and bacterial infection groups. By applying canonical discriminant analysis, it was possible to classify the patients into the different groups. Validation analyses displayed good results for neuropediatric patients with no-immune diseases and for viral meningitis patients, followed by the other groups. This study provides initial evidence of a more efficient approach to promote the timely classification of patients with viral and bacterial infections and acquired autoimmune disorders. Through canonical equations, we have validated a new tool that aids in the early and differential diagnosis of these neuroinflammatory conditions.

In this article, we review the state-of-the-art analysis of different biomarkers in the cerebrospinal fluid for the diagnosis of genetically conditioned, rare, neurometabolic diseases, including glucose transport defects, neurotransmitter (dopamine, serotonin, and gamma-aminobutyric acid) and pterin deficiencies, and vitamin defects (folate, vitamin B6, and thiamine) that affect the brain. The analysis of several key metabolites are detailed, which thus highlights the preanalytical and analytical factors that should be cautiously controlled to avoid misdiagnosis; moreover, these factors may facilitate an adequate interpretation of the biochemical profiles in the context of severe neuropediatric disorders. Secondary disturbances in these biomarkers, which are associated with other genetic or environmental conditions, are also detailed. Importantly, the early biochemical identification of biochemical disturbances in the cerebrospinal fluid may improve the clinical outcomes of a remarkable number of patients, who may exhibit good neurologic outcomes using the available therapies for these disorders.

Objective The mechanisms of the ketogenic diet remain unclear, but several predictors of response have been proposed. We aimed is to study the relationship between the etiology of epilepsy, cerebrospinal fluid neurotransmitters, pterins, and amino acids, and response to a ketogenic diet. Methods We studied 60 patients who began classic ketogenic diet treatment for refractory epilepsy. In 24 of 60 individuals, we analyzed cerebrospinal fluid neurotransmitters, pterins, and amino acids in baseline conditions. Mean age at epilepsy onset was 24 months, 83.3% were focal epilepsies, and in 51.7% the etiology of the epilepsy was unknown. Results Six months after initiating the ketogenic diet, it was effective (greater than a 50% reduction in seizure frequency) in 31.6% of patients. We did not find a link between rate of efficacy for the ketogenic diet and etiologies of epilepsy, nor did we find a link between the rate of efficacy for the ketogenic diet and cerebrospinal fluid pterins and biogenic amines concentrations. However, we found statistically significant differences for lysine and arginine values in the cerebrospinal fluid between ketogenic diet responders and nonresponders, but not for the other amino acids analyzed. Significance The values of some amino acids were significantly different in relationship with the ketogenic diet efficacy; however, the epilepsy etiology and the cerebrospinal fluid biogenic amine and pterin values were not.

Cerebral folate deficiency is defined as any neurological condition associated with low cerebrospinal fluid folate concentrations. It is becoming increasingly associated with several neurological diseases, either genetic or environmental. Treatment of cerebral folate deficiency by folate supplementation is generally effective, improving the neurological outcome of some patients. However, to treat cerebral folate deficiency, the proper choice of one of the available folate forms is essential. The distinct brain folate metabolism features compared with peripheral folate metabolic pathways strongly suggest the investigation of different folate forms, such as the biologically active folinic acid and 5-methyltetrahydrofolate, since they are efficiently transported to the brain. Regarding the oral doses of the different folate forms, despite the fact that there are some recommendations, there is no general consensus. Further investigation and designing clinical trials are advisable to elucidate these aspects.

Mitochondrial diseases are a group of genetic disorders leading to the dysfunction of mitochondrial energy metabolism pathways. We aimed to assess the clinical phenotype and the biochemical cerebrospinal fluid (CSF) biogenic amine profiles of patients with different diagnoses of genetic mitochondrial diseases. We recruited 29 patients with genetically confirmed mitochondrial diseases harboring mutations in either nuclear or mitochondrial DNA (mtDNA) genes. Signs and symptoms of impaired neurotransmission and neuroradiological data were recorded. CSF monoamines, pterins, and 5-methyltetrahydrofolate (5MTHF) concentrations were analyzed using high-performance liquid chromatography with electrochemical and fluorescence detection procedures. The mtDNA mutations were studied by Sanger sequencing, Southern blot, and real-time PCR, and nuclear DNA was assessed either by Sanger or next-generation sequencing. Five out of 29 cases showed predominant dopaminergic signs not attributable to basal ganglia involvement, harboring mutations in different nuclear genes. A chi-square test showed a statistically significant association between high homovanillic acid (HVA) values and low CSF 5-MTHF values (chi-square = 10.916; p = 0.001). Seven out of the eight patients with high CSF HVA values showed cerebral folate deficiency. Five of them harbored mtDNA deletions associated with Kearns-Sayre syndrome (KSS), one had a mitochondrial point mutation at the mtDNA ATPase6 gene, and one had a POLG mutation. In conclusion, dopamine deficiency clinical signs were present in some patients with mitochondrial diseases with different genetic backgrounds. High CSF HVA values, together with a severe cerebral folate deficiency, were observed in KSS patients and in other mtDNA mutation syndromes.

Altres ajuts: This work is funded by the European Regional Development Fund (FEDER) and the Fundació La Marató TV3 (20,143,130 to BPD). LMS has a grant from Fundació Sant Joan de Déu. MAK holds a Wellcome Intermediate Clinical Fellowship. The SLC39A14, SLC30A10 and SLC39A8 are considered to be key genes involved in manganese (Mn) homeostasis in humans. Mn levels in plasma and urine are useful tools for early recognition of these disorders. We aimed to explore further biomarkers of Mn deposition in the central nervous system in two siblings presenting with acute dystonia and hypermanganesemia due to mutations in SLC39A14. These biomarkers may help clinicians to establish faster and accurate diagnosis and to monitor disease progression after chelation therapy is administered. A customized gene panel for movement disorders revealed a novel missense variant (c.311G > T; p.Ser104Ile) in SLC39A14 gene in two siblings presenting at the age of 10 months with acute dystonia and motor regression. Mn concentrations were analyzed using inductively coupled mass spectrometry in plasma and cerebrospinal fluid, disclosing elevated Mn levels in the index case compared to control patients. Surprisingly, Mn values were 3-fold higher in CSF than in plasma. We quantified the pallidal index, defined as the ratio between the signal intensity in the globus pallidus and the subcortical frontal white matter in axial T1-weighted MRI, and found significantly higher values in the SLC39A14 patient than in controls. These values increased over a period of 10 years, suggesting the relentless pallidal accumulation of Mn. Following genetic confirmation, a trial with the Mn chelator NaCaEDTA led to a reduction in plasma Mn, zinc and selenium levels. However, parents reported worsening of cervical dystonia, irritability and sleep difficulties and chelation therapy was discontinued. Our study expands the very few descriptions of patients with SLC39A14 mutations. We report for the first time the elevation of Mn in CSF of SLC39A14 mutated patients, supporting the hypothesis that brain is an important organ of Mn deposition in SLC39A14-related disease. The pallidal index is an indirect and non-invasive method that can be used to rate disease progression on follow-up MRIs. Finally, we propose that patients with inherited defects of manganese transport should be initially treated with low doses of NaCaEDTA followed by gradual dose escalation, together with a close monitoring of blood trace elements in order to avoid side effects.

Pyridoxal phosphate (PLP) is the active form of vitamin B6 and a cofactor in many enzyme reactions including neurotransmitter metabolism. PLP metabolism disturbances may mostly lead to refractory seizures. In this report, we review the main pathophysiological factors related with PLP deficiency and our experience in PLP treatment in pediatric patients with low-normal cerebrospinal fluid PLP values who presented epilepsy. Only one case had a definite diagnosis (Phelan-McDermid syndrome). The results of extensive metabolic workups and targeted genetic studies were normal for all patients. In 5 cases, the response to PLP supplementation (10-30mg/kg/d) was initially positive. PLP adverse reactions were noticed in 4 patients and PLP was discontinued; however, one of the most noticeable symptoms was an asymptomatic increase in liver enzymes. These negative results with PLP supplementation are worth reporting, to improve the information we use to treat our patients.

Aim To determine the prevalence of dopaminergic abnormalities in 1388 children with neurological disorders, and to analyse their clinical, neuroradiological, and electrophysiological characteristics. Method We studied biogenic amines in 1388 cerebrospinal fluid (CSF) samples from children with neurological disorders (mean age 3y 10mo, SD 4y 5mo; 712 males, 676 females. Correlations among CSF homovanillic acid (HVA) values and other biochemical, clinical, neuroradiological, and electrophysiological parameters were analysed. Results Twenty-one patients with primary dopaminergic deficiencies were identified. Of the whole sample, 20% showed altered HVA. We report neurological diseases with abnormal CSF HVA values such as pontocerebellar hypoplasia, perinatal asphyxia, central nervous system infections, mitochondrial disorders, and other genetic diseases. Overlapping HVA levels between primary and secondary dopamine deficiencies were observed. Prevalence of low CSF HVA levels was significantly higher in neonatal patients (χ2=84.8, p

Thiamine transporter-2 deficiency is caused by mutations in the SLC19A3 gene. As opposed to other causes of Leigh syndrome, early administration of thiamine and biotin has a dramatic and immediate clinical effect. New biochemical markers are needed to aid in early diagnosis and timely therapeutic intervention. Thiamine derivatives were analysed by high performance liquid chromatography in 106 whole blood and 38 cerebrospinal fluid samples from paediatric controls, 16 cerebrospinal fluid samples from patients with Leigh syndrome, six of whom harboured mutations in the SLC19A3 gene, and 49 patients with other neurological disorders. Free-thiamine was remarkably reduced in the cerebrospinal fluid of five SLC19A3 patients before treatment. In contrast, free-thiamine was slightly decreased in 15.2% of patients with other neurological conditions, and above the reference range in one SLC19A3 patient on thiamine supplementation. We also observed a severe deficiency of free-thiamine and low levels of thiamine diphosphate in fibroblasts from SLC19A3 patients. Surprisingly, pyruvate dehydrogenase activity and mitochondrial substrate oxidation rates were within the control range. Thiamine derivatives normalized after the addition of thiamine to the culture medium. In conclusion, we found a profound deficiency of free-thiamine in the CSF and fibroblasts of patients with thiamine transporter-2 deficiency. Thiamine supplementation led to clinical improvement in patients early treated and restored thiamine values in fibroblasts and cerebrospinal fluid.

Objectives Thiamine transporter-2 (hTHTR2) deficiency due to SLC19A3 mutations is a potentially reversible cause of Leigh syndrome for which no biochemical markers are currently available. Our aim was to assess the sensitivity of thiamine quantification in cerebrospinal fluid (CSF) and fibroblasts from patients with Leigh encephalopathy and SLC19A3 defects as compared with other causes of Leigh syndrome. Methods Thiamine vitamers (free-thiamine, thiamine monophosphate (TMP) and thiamine diphosphate (TDP)) were analyzed by HPLC-fluorescence detection in whole-blood and cerebrospinal fluid (CSF) samples from 106 and 38 paediatric controls, respectively. Results were compared with patients with Leigh syndrome due to SLC19A3 defects (N=6) and mitochondrial respiratory chain defects (N=9). In all but one SLC19A3 patient, samples were collected before thiamine supplementation. Thiamine vitamers were also analyzed by HPLC in fibroblasts from SLC19A3 patients (N=3) and patients with other metabolic defects (N=6). Results A negative correlation between thiamine isoforms and age was detected in whole-blood and CSF, thus three reference intervals were established for free-thiamine and two intervals for TMP and TDP. Free-thiamine was severely reduced in five non-treated SLC19A3 patients CSF, but not TMP and TPP. The SLC19A3 patient under thiamine supplementation showed thiamine values above reference range. Nine Leigh patients with mitochondrial defects showed normal o slightly reduced values for CSF thiamine. In SLC19A3 patient's fibroblasts, a reduction in free-thiamine was detected as compared with control sample. These values normalized after thiamine was added to the culture medium. Conclusion SLC19A3 patients show a profound deficiency of free-thiamine in the CSF that allows their identification from other causes of Leigh syndrome. SLC19A3 is essential to maintain CSF thiamine homeostasis and to prevent brain damage. Thiamine overload can supply the SLC19A3 defect and restore thiamine values in fibroblasts and CSF, probably by an alternative transport system.

The measurement of γ-aminobutyric acid (GABA) is suitable for investigating various neurological disorders. In this study, a sensitive and selective method for free GABA quantification in cerebrospinal fluid (CSF) has been standardised. This method is based on CE with LIF detection using 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-F) as a derivatisating agent. The reaction conditions (NBD-F concentration, pH, temperature and reaction time) and the electrophoretic parameters (run buffer composition and pH and separation voltage) were optimised to obtain the maximum derivatisation efficiency and electrophoretic resolution. The best resolution was obtained using 200 mM sodium borate, 10 mM SDS, 8.5 mM β-CD, pH 10 and 20 kV voltage. The method was linear in the concentration range of 2.5-1000 nM with good inter- and intra-assay precision values. The effects of CSF handling on free GABA concentrations were also evaluated. Our results show that the time delay between CSF collection and freezing strongly increases the CSF GABA values. Age-related reference values were established in 55 paediatric controls. The influence of antiepileptic therapy on free CSF GABA was studied in 38 neuropaediatric patients. Significantly, higher GABA values were obtained in patients taking valproic acid or vigabatrin therapy, which are antiepileptic drugs that modulate GABA metabolism.