Rare co-occurrence of multiple sclerosis and Wilson's disease - case report.

BACKGROUND: Wilson's disease is a hereditary disorder of copper metabolism resulting mainly in hepatic, neurological, and psychiatric symptoms. Multiple sclerosis (MS) is an immune-mediated demyelinating disease affecting the central nervous system (CNS). The co-occurrence of these two, although not unheard of in literature, is still considered to be very rare and can give rise to diagnostic difficulties. Also, comorbidity in MS highly influences quality of life and disease progression, which makes the timely diagnosis and treatment of these conditions essential. CASE PRESENTATION: The aim of this study is to present a patient exhibiting symptoms of both MS and Wilson's disease, as well as to conduct a detailed review of previously reported cases. The patient's neurological symptoms (sensory disorder) as well as MRI and CSF findings were characteristic for MS. The diagnosis of MS preceded that of Wilson's disease and was relatively mild in course. Currently, the patient receives cladribine as an immunomodulatory treatment after escalation from glatiramer acetate therapy. Apart from one episode of acute hepatic decompensation, during which transfusion, albumin supplementation and diuretic treatment was necessary, Wilson's disease manifested as chronic impairment of liver function. The diagnosis of Wilson's disease was established by the analysis of serum coeruloplasmin levels, histological examination and genetic findings. Continuous oral penicillamine therapy led to the slow normalization of hepatic function and significant amelioration of the patient's symptoms. Correlating with cases previously reported, the course of MS was relatively mild, and like in three out of four other known cases, the symptoms of Wilson's disease were mostly restricted to hepatic dysfunction. CONCLUSION: The case presented in our report is similar to those reported before. The co-occurrence of the two diseases seems to be more a coincidence than a sharing of common factors in their pathogenesis; however, they are considered to influence one another. Regarding rare co-occurrences such as this one, every new case is of high importance, as it enables a better evaluation and understanding of the clinical presentations that are more characteristic of these cases, thus aiding the estimation of disease course as well as possible therapeutic choices.

Cerebrospinal Fluid Neurofilament Light Chain Is Associated with Kynurenine Pathway Metabolite Changes in Multiple Sclerosis.

Neurofilament light (NFL) has proved to be a good prognostic factor in multiple sclerosis (MS), as its level is proportionally elevated with extended neuraxonal damage. The involvement of the kynurenine pathway in neuroinflammation has been proved. The precursor of this pathway is the essential amino acid tryptophan, which is catabolized 95% towards kynurenine metabolites. Quinolinic acid (QUIN) within the brain is only produced in activated microglia and macrophages, leading to axonal degeneration via the activation of N-Methyl-D-aspartate receptors. Neopterin is a biomarker for inflammation produced by macrophages. The association of these biomarkers has not previously been investigated. Our aim was to assess whether there is an association of the neurodegenerative biomarker NFL with the markers of neuroinflammation, e.g., kynurenine metabolites and neopterin, in the cerebrospinal fluid (CSF). CSF samples of patients with MS (pwMS; n = 37) and age-matched controls (n = 22) were compared for NFL levels by ELISA, while the kynurenine pathway metabolites tryptophan and neopterin were detected with mass spectrometry. Spearman's correlation showed that NFL is an independent predictor of neurological disability in the MS group. Significant correlations were found between NFL, neopterin, and QUIN, and between kynurenine and neopterin. Receiver operating characteristic (ROC) curve analysis was used to plot the top three best predictors of MS-related disability that yielded the best specificity and sensitivity. Normalized NFL (AUC: 0.923), QUIN (AUC: 0.803), and neopterin (AUC: 0.843) were the best independent predictors of neurological disability in pwMS. The CSF NFL and CSF QUIN, together with neopterin, were elevated in the CSF of pwMS compared to controls. The combination of the neurodegenerative biomarkers together with biomarkers of neuroinflammation could provide additional information on the underlying pathomechanism of disease activity, which is essential for the identification of patients at risk of developing cumulative disabilities.

CANOMAD syndrome with respiratory failure.

CANOMAD (chronic ataxic neuropathy, ophthalmoplegia, M-protein agglutination, disialosyl antibodies) syndrome is a rare polyneuropathy. IgM paraproteins react with ganglioside-containing disialylated epitopes resulting in dorsal root ganglionopathy and B-lymphocyte infiltration of cranial and peripheral nerves. Clinical features include ataxia, slight muscle weakness, areflexia, sensory- and cranial nerve symptoms. Case studies have reported the efficacy of rituximab and intravenous immunoglobulin (IVIg) treatments. We present the case of a 57-year-old man, who had difficulty walking, with numbness and clumsiness in all limbs. He had areflexia, vibratory sensation loss and ataxia. Laboratory tests showed IgM monoclonal components and disialosyl antibodies in the serum. Nerve conduction studies indicated severe sensorimotor demyelinating polyneuroradiculopathy. Despite IVIg and rituximab treatments, the patient's disease course gradually worsened and he died of respiratory failure. Neuropathological examination revealed dorsal column- and dorsal root atrophy with mixed mononuclear cell infiltration. This article aims to draw attention to this syndrome, and the use of early potent immunosuppressive treatment to improve patients' quality of life.

[The role of MRI in measuring the effectivity of disease modifying treatments I]. / Az MRI helye a sclerosis multiplex kezelés hatékonyságának megítélésében I.: mérési markerek.

MRI has a significant role in the diagnosis of multiple sclerosis. The newer and newer treatment options of the disease make it necessary to monitor the effectiveness of the therapy. Besides the clinical signs (clinical relapses and progression), the different MRI parameters can also reflect the disease activity. In our current article we summarize those MRI markers, which best predict the long-term disability, based on the international standards.

[The role of MRI in measuring the effectivity of disease modifying treatments II]. / Az MRI helye a sclerosis multiplex kezelés hatékonyságának megítélésében II.: mérési protokollok.

The paraclinical examinations, principally the MRI have an increasing significance in the diagnosis of multiple sclerosis. However, MRI markers also have a prominent role in monitoring of the disease-course and activity, and also in the planning of possible therapeutic changes. In accordance with previously published international guidelines, in this article we propose a protocol for the monitoring the treatment efficacy in multiple sclerosis. This could be the basis of a consensus based guideline to be implemented in Hungary.

Excitotoxins, Mitochondrial and Redox Disturbances in Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). There is increasing evidence that MS is not only characterized by immune mediated inflammatory reactions, but also by neurodegenerative processes. There is cumulating evidence that neurodegenerative processes, for example mitochondrial dysfunction, oxidative stress, and glutamate (Glu) excitotoxicity, seem to play an important role in the pathogenesis of MS. The alteration of mitochondrial homeostasis leads to the formation of excitotoxins and redox disturbances. Mitochondrial dysfunction (energy disposal failure, apoptosis, etc.), redox disturbances (oxidative stress and enhanced reactive oxygen and nitrogen species production), and excitotoxicity (Glu mediated toxicity) may play an important role in the progression of the disease, causing axonal and neuronal damage. This review focuses on the mechanisms of mitochondrial dysfunction (including mitochondrial DNA (mtDNA) defects and mitochondrial structural/functional changes), oxidative stress (including reactive oxygen and nitric species), and excitotoxicity that are involved in MS and also discusses the potential targets and tools for therapeutic approaches in the future.

How to minimize the risk for headache? A lumbar puncture practice questionnaire study.

Background - To lower the risk for post lumbar puncture (LP) headache the American Academy of Neurology (AAN) recommended using small bore atraumatic needles together with stylet reinsertion in a report from 2005. It is unclear whether these recommendations are followed or not. Objectives - To investigate the diagnostic LP preferences with respect to the AAN guidelines among neurologists by use of a short online questionnaire, and to review previously published literature on the subject. Results - A total of 284 respondents who performed diagnostic LPs completed the questionnaire. Almost half (41%) answered that they always use atraumatic needles. The most common reason (73%) for not using atraumatic needles was that these were not available. Less than half of the respondents who performed LPs had knowledge about the AAN guidelines for diagnostic LPs, and 48-76% agreed with the different recommendations therein. Five previously (1998-2015) published studies investigating LP practice among neurologists were identified. The reported frequency of atraumatic needle use (always/routinely) varied between 2 and 16%. Discussion - Atraumatic needle use was more common in this study compared with previous publications. There is still skepticism regarding some of the AAN recommendations, and needle availability appears to be the most important factor preventing atraumatic needle use. To increase the use of atraumatic needles we may perform additional studies investigating their potential benefits, and arrange training sessions for neurologists to increase their awareness and level of comfort with the atraumatic LP technique.

Kynurenines and Multiple Sclerosis: The Dialogue between the Immune System and the Central Nervous System.

Multiple sclerosis is an inflammatory disease of the central nervous system, in which axonal transection takes place in parallel with acute inflammation to various, individual extents. The importance of the kynurenine pathway in the physiological functions and pathological processes of the nervous system has been extensively investigated, but it has additionally been implicated as having a regulatory function in the immune system. Alterations in the kynurenine pathway have been described in both preclinical and clinical investigations of multiple sclerosis. These observations led to the identification of potential therapeutic targets in multiple sclerosis, such as synthetic tryptophan analogs, endogenous tryptophan metabolites (e.g., cinnabarinic acid), structural analogs (laquinimod, teriflunomid, leflunomid and tranilast), indoleamine-2,3-dioxygenase inhibitors (1MT and berberine) and kynurenine-3-monooxygenase inhibitors (nicotinylalanine and Ro 61-8048). The kynurenine pathway is a promising novel target via which to influence the immune system and to achieve neuroprotection, and further research is therefore needed with the aim of developing novel drugs for the treatment of multiple sclerosis and other autoimmune diseases.

Can somatosensory evoked potentials predict disease course in early multiple sclerosis patients?

BACKGROUND: Multiple sclerosis (MS) is an autoimmune degenerating disease, where myelin degradation as well as axonal loss is present. PURPOSE: To asses whether recording the middle-latency components of the median nerve somatosensory evoked potentials (SEPs) increases the diagnostic sensitivity in patients with MS, and to investigate whether any of the abnormalities correlates with the severity of the clinical signs and predicts future outcome. METHODS: Twenty consecutive MS patients at early onset were included. Median and tibial nerve SEPs were recorded at the time of the referral. Extended Disability Status Scale (EDSS) and Multiple Sclerosis Severity Score (MSSS) were assessed at the time of the referral and after 5-year followup. RESULTS: Recording the middle-latency components increased the sensitivity of the median nerve SEPs from 50% to 75%. The overall sensitivity of the SEPs (i.e. including also tibial nerve SEPs) modestly increased (from 80% to 90%). The amplitude of the cortical N20 potential of the median nerve was inversely correlated to the clinical severity. None of the parameters could predict the future outcome. CONCLUSIONS: Our results provide neurophysiological evidence for the role of axonal lesions in the clinical disability of the patients with MS.

The Tryptophan-Kynurenine Metabolic System Is Suppressed in Cuprizone-Induced Model of Demyelination Simulating Progressive Multiple Sclerosis.

Progressive multiple sclerosis (MS) is a chronic disease with a unique pattern, which is histologically classified into the subpial type 3 lesions in the autopsy. The lesion is also homologous to that of cuprizone (CPZ) toxin-induced animal models of demyelination. Aberration of the tryptophan (TRP)-kynurenine (KYN) metabolic system has been observed in patients with MS; nevertheless, the KYN metabolite profile of progressive MS remains inconclusive. In this study, C57Bl/6J male mice were treated with 0.2% CPZ toxin for 5 weeks and then underwent 4 weeks of recovery. We measured the levels of serotonin, TRP, and KYN metabolites in the plasma and the brain samples of mice at weeks 1, 3, and 5 of demyelination, and at weeks 7 and 9 of remyelination periods by ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) after body weight measurement and immunohistochemical analysis to confirm the development of demyelination. The UHPLC-MS/MS measurements demonstrated a significant reduction of kynurenic acid, 3-hydoxykynurenine (3-HK), and xanthurenic acid in the plasma and a significant reduction of 3-HK, and anthranilic acid in the brain samples at week 5. Here, we show the profile of KYN metabolites in the CPZ-induced mouse model of demyelination. Thus, the KYN metabolite profile potentially serves as a biomarker of progressive MS and thus opens a new path toward planning personalized treatment, which is frequently obscured with immunologic components in MS deterioration.

Treatment with Cladribine Tablets Beyond Year 4: A Position Statement by Southeast European Multiple Sclerosis Centers.

Based on the results of the pivotal CLARITY study, cladribine tablets were approved for use in the European Union in 2017 as a high-efficacy therapy for highly active relapsing-remitting multiple sclerosis (MS). Cladribine tablets are used as an induction therapy: half of the total dose is given in year 1 and the other half in year 2. In the CLARITY Extension trials, repeating the dose routinely in years 3 and 4, was not associated with significantly improved disease control. However, there is very limited evidence on how to manage people with MS (pwMS) beyond year 4, which is increasingly important because more and more patients are now ≥ 4 years after cladribine treatment. Overall, postapproval data show that treatment with two cladribine cycles effectively controls disease activity in the long term. However, there is general agreement that some pwMS with suboptimal response could benefit from retreatment. This study reviews the practical aspects of using cladribine tablets, summarizes the evidence from clinical trials and real-world studies on the safety and efficacy of cladribine, and proposes a treatment algorithm developed by expert consensus for pwMS previously treated with cladribine. In brief, we propose that additional courses of cladribine tablets should be considered in patients with minimal (no relapses, 1-2 new lesions) or moderate (1 relapse, 3-4 new lesions) disease activity, while significant disease activity (> 1 relapse, > 3 new lesions) or progression should warrant a switch to another high-efficacy treatment (HET). More evidence is needed to improve the treatment guidelines for pwMS who previously received cladribine.

Treatment of relapsing multiple sclerosis in Hungary - consensus recommendation from the Hungarian neuroimmunology society.

Multiple sclerosis (MS) may impact quality of life, careers and family plans of the affected individuals. The current treatments with disease modifying therapies aim to prevent people with MS (pwMS) from disability accumulation and progression. Different countries have different reimbursement policies resulting in inequalities in patient care among geographical regions. Access to anti-CD20 therapies for relapsing MS is restricted in Hungary because therapy of individual cases only is reimbursed. In the light of the latest research and national guidelines, 17 Hungarian MS experts agreed on 8 recommendations regarding relapsing pwMS using the Delphi round method. Strong agreement (> 80%) was achieved in all except one recommendation after three rounds, which generated a fourth Delphi round. The experts agreed on treatment initiation, switch, follow-up and discontinuation, as well as on special issues such as pregnancy, lactation, elderly population, and vaccination. Well-defined national consensus protocols may facilitate dialogue between policymakers and healthcare professionals and thus contribute to better patient care in the long run.

Cladribine tablets in people with relapsing multiple sclerosis: A real-world multicentric study from southeast European MS centers.

BACKGROUND: Cladribine is an oral disease-modifying drug authorized by the European Medicine Agency for the treatment of highly active relapsing multiple sclerosis (MS). OBJECTIVES: To provide real-world evidence of cladribine's effectiveness and safety in people with MS (pwMS). METHODS: A retrospective observational multi-center, multi-national study of pwMS who were started on cladribine tablets in ten centers from five European countries. RESULTS: We identified 320 pwMS treated with cladribine tablets. The most common comorbidities were arterial hypertension and depression. Three patients had resolved hepatitis B infection, while eight had positive Quantiferon test prior to cladribine commencement. There were six pwMS who had malignant diseases, but all were non-active. During year 1, 91.6% pwMS did not have EDSS worsening, 86.9% were relapse-free and 72.9% did not have MRI activity. During the second year, 90.2% did not experience EDSS worsening, 86.5% were relapse-free and 75.5% did not have MRI activity. NEDA-3 was present in 58.0% pwMS in year 1 and in 54.2% in year 2. In a multivariable logistic regression model age positively predicted NEDA-3 in year 1. The most common adverse events were infections and skin-related adverse events. Lymphopenia was noted in 54.7% of pwMS at month 2 and in 35.0% at month 6. Two pwMS had a newly discovered malignant disease, one breast cancer, and one melanoma, during the first year of treatment. CONCLUSION: Our real-world data on the effectiveness and safety of cladribine tablets are comparable to the pivotal study and other real-world data with no new safety signals.

The role of kynurenines in the pathomechanism of amyotrophic lateral sclerosis and multiple sclerosis: therapeutic implications.

Tryptophan is one of the essential amino acids, 80% of which is catabolised in the extrahepatic tissues by indoleamine-2,3-dioxygenase (IDO), the rate-limiting enzyme of the kynurenine pathway. Metabolites along the kynurenine pathway have been implicated to play a role in the pathomechanism of neuroinflammatory and neurodegenerative disorders. Changes in the concentration levels of kynurenines can shift the balance to pathological conditions. The ability to influence the metabolism towards the neuroprotective branch of the kynurenine pathway, i.e. towards kynurenic acid (KYNA) synthesis, may be one option in preventing neurodegenerative diseases. Three potential therapeutic strategies could be feasible to develop drugs to live up to expectations: (1) chemically related drugs with better bioavailability and higher affinity to the binding sites of excitatory receptors; (2) prodrugs of KYNA, which easily cross the blood-brain barrier combined with an inhibitor of organic acid transport for enhancement of the brain KYNA concentration; (3) inhibitors of enzymes of the kynurenine pathway. In this review, we focus on aspects of the pathomechanism and therapeutic possibilities of amyotrophic lateral sclerosis and multiple sclerosis that may be influenced by kynurenines.

Proteomic analysis of cerebrospinal fluid in a fulminant case of multiple sclerosis.

Multiple Sclerosis (MS) is a chronic disease, but in rare fulminant cases rapid progression may lead to death shortly after diagnosis. Currently there is no diagnostic test to predict disease course. The aim of this study was to identify potential biomarkers/proteins related to rapid progression. We present the case history of a 15-year-old male MS patient. Cerebrospinal fluid (CSF) was taken at diagnosis and at the time of rapid progression leading to the patient's death. Using isobaric tag labeling and nanoflow liquid chromatography in conjunction with matrix assisted laser desorption/ionization time of flight tandem mass spectrometry we quantitatively analyzed the protein content of two CSF samples from the patient with fulminant MS as well as one relapsing-remitting (RR) MS patient and one control headache patient, whose CSF analysis was normal. Seventy-eight proteins were identified and seven proteins were found to be more abundant in both fulminant MS samples but not in the RR MS sample compared to the control. These proteins are involved in the immune response, blood coagulation, cell proliferation and cell adhesion. In conclusion, in this pilot study we were able to show differences in the CSF proteome of a rapidly progressing MS patient compared to a more typical clinical form of MS and a control subject.

Association between microglial activation and serum kynurenine pathway metabolites in multiple sclerosis patients.

BACKGROUND: Microglial activation associates with MS progression but it is unclear what drives their persistent pro-inflammatory state. Metabolites of the kynurenine pathway (KP), the main metabolism route of tryptophan, can influence the function of brain innate immune cells. OBJECTIVE: To investigate whether tryptophan metabolites in blood associate with TSPO-PET measurable microglial activation in MS brain. METHODS: Microglial activation was detected using PET imaging and the TSPO-binding radioligand [11C]PK11195. Distribution volume ratios (DVR) for specific [11C]PK11195-binding in the normal appearing white matter (NAWM), lesions, and thalamus were calculated. Ultrahigh performance liquid chromatography-tandem mass spectrometry was used to measure serum levels of tryptophan and kynurenine pathway metabolites. RESULTS: The study cohort consisted of 48 MS patients. Increased DVR in the NAWM and thalamus correlated with decreased serum 3-hydroxykynurenine level (R = -0.31, p = 0.031 and R = -0.32, p = 0.028). Increased EDSS correlated with decreased 3-hydroxykynurenine and xanthurenic acid (R = -0.36, p = 0.012 and R = -0.31, p = 0.034) and increased DVR in the NAWM and thalamus (R = 0.33, p = 0.023 and R = 0.34, p = 0.020, respectively). CONCLUSIONS: This clinical study demonstrates an association between low serum 3-hydroxykynurenine and high microglial activation in MS. Further investigations are warranted for elucidation of the biological mechanisms behind this association.

Validation of the Fatigue Impact Scale in Hungarian patients with multiple sclerosis.

PURPOSE: Fatigue is one of the most frequent complaints of patients with multiple sclerosis (MS). The Fatigue Impact Scale (FIS), one of the 30 available fatigue questionnaires, is commonly applied because it evaluates multidimensional aspects of fatigue. The main purposes of this study were to test the validity, test-retest reliability, and internal consistency of the Hungarian version of the FIS. METHODS: One hundred and eleven MS patients and 85 healthy control (HC) subjects completed the FIS and the Beck Depression Inventory, a large majority of them on two occasions, 3 months apart. RESULTS: The total FIS score and subscale scores differed statistically between the MS patients and the HC subjects in both FIS sessions. In the test-retest reliability assessment, statistically, the intraclass correlation coefficients were high in both the MS and HC groups. Cronbach's alpha values were also notably high. CONCLUSIONS: The results of this study indicate that the FIS can be regarded as a valid and reliable scale with which to improve our understanding of the impact of fatigue on the health-related quality of life in MS patients without severe disability.

Kynurenines and Neurofilament Light Chain in Multiple Sclerosis.

Multiple sclerosis is an autoimmune, demyelinating, and neurodegenerative disease of the central nervous system. In recent years, it has been proven that the kynurenine system plays a significant role in the development of several nervous system disorders, including multiple sclerosis. Kynurenine pathway metabolites have both neurotoxic and neuroprotective effects. Moreover, the enzymes of the kynurenine pathway play an important role in immunomodulation processes, among others, as well as interacting with neuronal energy balance and various redox reactions. Dysregulation of many of the enzymatic steps in kynurenine pathway and upregulated levels of these metabolites locally in the central nervous system, contribute to the progression of multiple sclerosis pathology. This process can initiate a pathogenic cascade, including microglia activation, glutamate excitotoxicity, chronic oxidative stress or accumulated mitochondrial damage in the axons, that finally disrupt the homeostasis of neurons, leads to destabilization of neuronal cell cytoskeleton, contributes to neuro-axonal damage and neurodegeneration. Neurofilaments are good biomarkers of the neuro-axonal damage and their level reliably indicates the severity of multiple sclerosis and the treatment response. There is increasing evidence that connections exist between the molecules generated in the kynurenine metabolic pathway and the change in neurofilament concentrations. Thus the alterations in the kynurenine pathway may be an important biomarker of the course of multiple sclerosis. In our present review, we report the possible relationship and connection between neurofilaments and the kynurenine system in multiple sclerosis based on the available evidences.

Cuprizone markedly decreases kynurenic acid levels in the rodent brain tissue and plasma.

BACKGROUND: The kynurenine (KYN) pathway (KP) of the tryptophan (TRP) metabolism seems to play a role in the pathomechanism of multiple sclerosis (MS). Cuprizone (CPZ) treated animals develop both demyelination (DEM) and remyelination (REM) in lack of peripheral immune response, such as the lesion pattern type III and IV in MS, representing primary oligodendrogliopathy. OBJECTIVE: To measure the metabolites of the KP in the CPZ treated animals, including TRP, KYN and kynurenic acid (KYNA). We proposed that KYNA levels might be decreased in the CPZ-induced demyelinating phase of the animal model of MS, which model represents the progressive phase of the disease. METHODS: A total of 64 C57Bl/6J animals were used for the study. Immunohistochemical (IHC) measurements were performed to prove the effect of CPZ, whereas high-performance liquid chromatography (HPLC) was used to quantify the metabolites of the KP (n = 10/4 groups; DEM, CO1, REM, CO2). RESULTS: IHC measurements proved the detrimental effects of CPZ. HPLC measurements demonstrated a decrease of KYNA in the hippocampus (p < 0.05), somatosensory cortex (p < 0.01) and in plasma (p < 0.001). CONCLUSION: This is the first evidence of marked reduction in KYNA levels in a non-immune mediated model of MS. Our results suggest an involvement of the KP in the pathomechanism of MS, which needs to be further elucidated.

Simultaneous determination of 30 neurologically and metabolically important molecules: A sensitive and selective way to measure tyrosine and tryptophan pathway metabolites and other biomarkers in human serum and cerebrospinal fluid.

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.