Abnormal VLCADD newborn screening resembling MADD in four neonates with decreased riboflavin levels and VLCAD activity.

Early detection of congenital disorders by newborn screening (NBS) programs is essential to prevent or limit disease manifestation in affected neonates. These programs balance between the detection of the highest number of true cases and the lowest number of false-positives. In this case report, we describe four unrelated cases with a false-positive NBS result for very-long-chain acyl-CoA dehydrogenase deficiency (VLCADD). Three neonates presented with decreased but not deficient VLCAD enzyme activity and two of them carried a single heterozygous ACADVL c.1844G>A mutation. Initial biochemical investigations after positive NBS referral in these infants revealed acylcarnitine and organic acid profiles resembling those seen in multiple acyl-CoA dehydrogenase deficiency (MADD). Genetic analysis did not reveal any pathogenic mutations in the genes encoding the electron transfer flavoprotein (ETF alpha and beta subunits) nor in ETF dehydrogenase. Subsequent further diagnostics revealed decreased levels of riboflavin in the newborns and oral riboflavin administration normalized the MADD-like biochemical profiles. During pregnancy, the mothers followed a vegan, vegetarian or lactose-free diet which probably caused alimentary riboflavin deficiency in the neonates. This report demonstrates that a secondary (alimentary) maternal riboflavin deficiency in combination with reduced VLCAD activity in the newborns can result in an abnormal VLCADD/MADD acylcarnitine profile and can cause false-positive NBS. We hypothesize that maternal riboflavin deficiency contributed to the false-positive VLCADD neonatal screening results.

Neurotoxicity including posterior reversible encephalopathy syndrome after initiation of calcineurin inhibitors in transplanted methylmalonic acidemia patients: Two case reports and review of the literature.

INTRODUCTION: New neurological symptoms in methylmalonic acidemia (MMA) patients after liver and/or kidney transplantation (LKT) are often described as metabolic stroke-like-events. Since calcineurin inhibitors (CNIs) are a well-known cause of new neurological symptoms in non-MMA transplanted patients, we investigated the incidence of CNI-induced neurotoxicity including posterior reversible encephalopathy syndrome (PRES) in post-transplanted MMA patients. METHODS: We report the two MMA patients treated with LKT in our center. Additionally, we performed a systematic review of case reports/series of post-transplanted MMA patients and determined if CNI-induced neurotoxicity/PRES was a likely cause of new neurological symptoms. Definite CNI-induced neurotoxicity was defined as new neurological symptoms during CNI treatment with symptom improvement after CNI dose reduction/discontinuation. PRES was defined as CNI-induced neurotoxicity with signs of vasogenic edema on brain magnetic resonance imaging (MRI)-scan post-transplantation. RESULTS: Our two MMA patients both developed CNI-induced neurotoxicity, one had PRES. In literature, 230 transplanted MMA patients were identified. Neurological follow-up was reported in 54 of them, of which 24 were excluded from analysis since no anti-rejection medication was reported. Thirty patients, all using CNI, were included. Sixteen patients (53%) had no new neurological symptoms post-transplantation and five patients (17%) had definite CNI neurotoxicity of whom two had PRES. Including our cases this results in a pooled incidence of 22% (7/32) definite CNI neurotoxicity and 9% PRES (3/32) in post-transplanted MMA patients on CNI. CONCLUSION: In MMA post-transplanted patients with new neurological symptoms CNI-induced neurotoxicity/PRES should be considered. Early recognition of CNI-induced neurotoxicity is essential to initiate dose reduction/discontinuation of CNI to minimize persistent neurologic damage and improve outcome. CONCISE ONE SENTENCE TAKE HOME MESSAGE: In all post-transplanted MMA patients with new neurological symptoms CNI-induced neurotoxicity/PRES should be considered, and directly reducing the dose/discontinuation of CNI is essential.

Untargeted Metabolomics-Based Screening Method for Inborn Errors of Metabolism using Semi-Automatic Sample Preparation with an UHPLC- Orbitrap-MS Platform.

Routine diagnostic screening of inborn errors of metabolism (IEM) is currently performed by different targeted analyses of known biomarkers. This approach is time-consuming, targets a limited number of biomarkers and will not identify new biomarkers. Untargeted metabolomics generates a global metabolic phenotype and has the potential to overcome these issues. We describe a novel, single platform, untargeted metabolomics method for screening IEM, combining semi-automatic sample preparation with pentafluorophenylpropyl phase (PFPP)-based UHPLC- Orbitrap-MS. We evaluated analytical performance and diagnostic capability of the method by analysing plasma samples of 260 controls and 53 patients with 33 distinct IEM. Analytical reproducibility was excellent, with peak area variation coefficients below 20% for the majority of the metabolites. We illustrate that PFPP-based chromatography enhances identification of isomeric compounds. Ranked z-score plots of metabolites annotated in IEM samples were reviewed by two laboratory specialists experienced in biochemical genetics, resulting in the correct diagnosis in 90% of cases. Thus, our untargeted metabolomics platform is robust and differentiates metabolite patterns of different IEMs from those of controls. We envision that the current approach to diagnose IEM, using numerous tests, will eventually be replaced by untargeted metabolomics methods, which also have the potential to discover novel biomarkers and assist in interpretation of genetic data.

Neonatal screening for profound biotinidase deficiency in the Netherlands: consequences and considerations.

Biotinidase deficiency is a rare inherited metabolic disorder that can cause severe neurological symptoms. To prevent severe clinical presentations, it was included in the Dutch neonatal screening programme in 2007. Since then the number of cases detected has been high. This study set out to describe the incidence of the disease, the clinical and demographic characteristics of the neonates identified and the type of mutations found. In the south-western Netherlands, 304 982 neonates were screened between 2007 and 2012; and 92 were identified for further testing. Confirmatory testing revealed 6 (7%) with a profound biotinidase deficiency (<10% enzyme activity), 44 (48%) with a partial deficiency (10-30%) and 42 (46%) with normal activity (>30%). All six patients whose profound deficiency was confirmed had enzyme activities below 15% on neonatal screening. Mutation analysis was performed in 61 neonates: 5 'profound', 35 'partial' and 21 'normal'. All five 'profound' cases had two severe mutations. Comparison with the northern Netherlands showed that the frequency and types of mutation were representative for the Netherlands as a whole. The most common mutation detected was c.[1330G>C] (p.(Asp444His); 34%), which is considered to be mild, followed by three severe mutations c.[1368A>C], c.[1595C>T] and c.[1330G>C;511G>A]. Seven new mutations were identified. We conclude that neonatal screening for profound biotinidase produces a high number of false positives. Biotinidase deficiency was profound in less than 10% of cases identified. As biotinidase activity lay below 15% on neonatal screening in all such cases, the screening threshold might be reduced to 15%.

Intrathecal glycine for pain and dystonia in complex regional pain syndrome.

Since glycinergic neurotransmission plays an important inhibitory role in the processing of sensory and motor information, intrathecal glycine (ITG) administration may be a potential therapy for both pain and movement disorders in patients with complex regional pain syndrome (CRPS). Aims of the current study, which is the first report on ITG in humans, were to evaluate its safety and efficacy. ITG treatment during 4 weeks was studied in CRPS patients with dystonia in the period before they received intrathecal baclofen treatment. Twenty patients were assessed and after exclusion of one patient, the remaining 19 patients were randomized in a double-blind placebo-controlled crossover study. Safety was assessed by clinical evaluation, blood examinations and electrocardiograms. Efficacy measures involved pain (numeric rating scale, McGill pain questionnaire), movement disorders (Burke-Fahn-Marsden dystonia rating scale, unified myoclonus rating scale, tremor research group rating scale), activity (Radboud skills questionnaire, walking ability questionnaire), and a clinical global impression (CGI) and patient's global impression score (PGI). Treatment-emergent adverse events were generally mild to moderate and not different from placebo treatment. During ITG treatment growth hormone levels were slightly increased. Although there was a trend to worsening on the CGI and PGI during ITG treatment, there were no significant differences between ITG and placebo treatment in any of the outcomes. ITG given over 4 weeks was ineffective for pain or dystonia in CRPS. Although no serious adverse events occurred, further studies are required to rule out potential neurotoxicity of ITG.

Rhamnose and rhamnitol in dual sugar permeability tests.

Rhamnose is one of the sugars regularly used to conduct the dual sugar permeability test. For more than 30 years, it has been assumed that rhamnose is an inert sugar not metabolized by the human body and only fermented by some colonic bacteria into rhamnulose. While conducting an investigation on gut permeability in children undergoing cardiac surgery, increased concentrations of rhamnitol were found in the urine samples. The present report suggests that rhamnose is not an inert sugar and it is partially metabolized into rhamnitol by the human body.

The effects of a diet enriched with alpha-lactalbumin on mood and cortisol response in unmedicated recovered depressed subjects and controls.

Alpha-lactalbumin is a tryptophan-rich protein fraction. A diet enriched with alpha-lactalbumin increases the ratio of tryptophan to the other large neutral amino acids, which may in turn increase brain serotonin content. In stress-vulnerable individuals, alpha-lactalbumin improved mood and attenuated the cortisol response after experimental stress. The aim of the present study was to investigate the effects of an alpha-lactalbumin-enriched diet on mood and stress response in recovered depressed subjects and healthy controls. Forty-three subjects (twenty-three recovered depressed and twenty healthy subjects) received alpha-lactalbumin and casein (placebo) on separate days, in a double-blind randomised crossover design. On both occasions, subjects underwent a stress test (an unsolvable mental arithmetic task with loud noise). The stress test affected mood in both conditions. Although the alpha-lactalbumin diet led to the expected rises in tryptophan and tryptophan:large neutral amino acids ratio, only minimal effects were found on mood and cortisol response to experimental stress. The results were the same for recovered depressed patients and controls. A 1 d diet enriched with alpha-lactalbumin is not sufficient to prevent a stress-induced mood deterioration or a cortisol response in unmedicated, recovered depressed subjects. Future studies may investigate the effects of longer-term diets or may investigate different samples (e.g. medicated patients).

Gut permeability in neonates after a stage 1 Norwood procedure.

OBJECTIVE: Intestinal mucosal ischemia can occur during and after cardiac surgery. Severe decreases in mucosal perfusion may be a causative factor for postoperative mortality or complications such as necrotizing enterocolitis. Mesenteric perfusion is challenged preoperatively due to an imbalance between the systemic and pulmonary circulations and challenged intraoperatively due to hypothermic circulatory arrest. We have investigated gut permeability in seven patients undergoing stage 1 of the Norwood procedure, applying the dual sugar permeability test with L-rhamnose and lactulose. DESIGN: Seven patients with hypoplastic left heart syndrome: clinical presentation, gut permeability findings, and outcome. SETTING: A 10-bed mixed pediatric intensive care unit in a university hospital. PATIENTS: Seven patients admitted for postoperative care after cardiac surgery. INTERVENTIONS: Determination of gut permeability with the dual sugar permeability test using lactulose and rhamnose. Intestinal permeability was measured after induction of anesthesia and 12 and 24 hrs later. MEASUREMENTS AND MAIN RESULTS: : All patients had abnormal lactulose/rhamnose ratios. One patient, who had a lactulose/rhamnose ratio 12 hrs after surgery of 2.3 (46-times normal), developed necrotizing enterocolitis postoperatively and died 3 days after surgery. CONCLUSIONS: Gut permeability as assessed by the dual sugar permeability test is abnormal in patients with hypoplastic left heart syndrome before and after surgery. Lactulose/rhamnose ratios 46 times the normal value reflect a highly permeable small intestine. This may be a sign of a low output state and may help to identify patients at risk of developing necrotizing enterocolitis.

Dexamethasone reduces gut permeability in pediatric cardiac surgery.

OBJECTIVES: Little attention has been paid to the effect of the systemic inflammatory response syndrome on intestinal dysfunction in the postoperative period. Several proinflammatory cytokines have been reported to increase the permeability of intestinal mucosa in vitro. We investigated the effect of dexamethasone on gut permeability in pediatric patients undergoing cardiac surgery by using the dual sugar permeability test and absorption of 2 other saccharides. METHODS: Thirty-four patients scheduled for cardiac surgery with cardiopulmonary bypass were prospectively randomized to either act as control subjects or to receive dexamethasone (1 mg . kg -1) during induction of anesthesia. Intestinal permeability was measured with 3-O-methyl-D-glucose, D-xylose, L-rhamnose, and lactulose administered orally after induction of anesthesia and 12 and 24 hours later. RESULTS: Lactulose/rhamnose ratios were increased from the outset in both groups (mean 0.57 [95% confidence interval, 0.24-0.91] for the control group and 0.76 [95% confidence interval, 0.35-1.17] for patients receiving dexamethasone). Although the ratios decreased 12 hours (0.29 [95% confidence interval, 0.17-0.42]) and 24 hours later (0.17 [95% confidence interval, 0.08-0.15]) in the dexamethasone group, in the control group there was a rise at 12 hours (0.77 [95% confidence interval, 0-1.64]), with a slight reduction 24 hours later (0.46 [95% confidence interval, 0.06-0.85]). CONCLUSIONS: Infants and children undergoing cardiac surgery with cardiopulmonary bypass show a significant reduction in gut permeability when dexamethasone is used during induction of anesthesia. Dexamethasone does not affect the intestinal barrier at the functional level, as assessed on the basis of 3-O-methyl-D-glucose and D-xylose absorption.