Association of plasma folate, vitamin B12 levels, and arsenic methylation capacity with developmental delay in preschool children in Taiwan.

Developmental delay has been associated with inefficient arsenic methylation capacity in preschool children. Folate and vitamin B12 are important nutrients that produce s-adenosylmethionine during single-carbon metabolism and provide methyl groups for arsenic methylation. The aim of the present study was to explore whether plasma folate and vitamin B12 levels influence arsenic methylation capacity and in turn are related to developmental delay in preschool children. A case-control study was conducted in 178 children with developmental delay and 88 normal children, who were recruited from Shin Kong Wu Ho-Su Memorial Teaching Hospital from August 2010 to March 2014. Arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV) in the urine was determined by high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Plasma folate and vitamin B12 levels were measured using a SimulTRAC-SNB radioassay. The results show that the combination of high plasma folate and high vitamin B12 levels were correlated with efficient arsenic methylation capacity (low MMAV %, low InAs %, and high DMAV %). High MMAV % significantly increased and high DMAV % and secondary methylation index decreased the odds ratio (OR) of developmental delay in a dose-dependent manner in both low plasma folate and low vitamin B12 (low/low) groups; the multivariate OR and 95% confidence interval were 5.01 (0.83-30.06), 0.21 (0.04-1.23), and 0.20 (0.03-1.20), respectively. This is the first study to show that the combination of high plasma folate and high vitamin B12 levels increases arsenic methylation capacity and indirectly decreases the OR of developmental delay in preschool children.

Predictive Role of Urinary Metabolic Profile for Abnormal MRI Score in Preterm Neonates.

BACKGROUND AND OBJECTIVE: Early identification of neonates at risk for brain injury is important to start appropriate intervention. Urinary metabolomics is a source of potential, noninvasive biomarkers of brain disease. We studied the urinary metabolic profile at 2 and 10 days in preterm neonates with normal/mild and moderate/severe MRI abnormalities at term equivalent age. METHODS: Urine samples were collected at two and 10 days after birth in 30 extremely preterm infants and analyzed using proton magnetic resonance spectroscopy. A 3 T MRI was performed at term equivalent age, and images were scored for white matter (WM), cortical grey matter (cGM), deep GM, and cerebellar abnormalities. Infants were divided in two groups: normal/mild and moderately/severely abnormal MRI scores. RESULTS: No significant clustering was seen between normal/mild and moderate/severe MRI scores for all regions at both time points. The ROC curves distinguished neonates at 2 and 10 days who later developed a markedly less mature cGM score from the others (2 d: area under the curve (AUC) = 0.72, specificity (SP) = 65%, sensitivity (SE) = 75% and 10 d: AUC = 0.80, SP = 78%, SE = 80%) and a moderately to severely abnormal WM score (2 d: AUC = 0.71, specificity (SP) = 80%, sensitivity (SE) = 72% and 10 d: AUC = 0.69, SP = 64%, SE = 89%). CONCLUSIONS: Early urinary spectra of preterm infants were able to discriminate metabolic profiles in patients with moderately/severely abnormal cGM and WM scores at term equivalent age. Urine spectra are promising for early identification of neonates at risk of brain damage and allow understanding of the pathogenesis of altered brain development.

Vitamin B12 Deficiency in Children With Infantile Spasms: A Case-Control Study.

There have been few case reports showing association of vitamin B12 deficiency with infantile spasms. We planned this study to see if there was an association of serum vitamin B12 deficiency in children with development of infantile spasms. Cases included children with infantile spasms of ages 6 months to 3 years. The controls were children in the same age group who had global developmental delay but no history of epileptic spasms. Mean serum vitamin B12, serum homocysteine, and urinary methylmalonic acid levels were measured in both groups and compared. Children with infantile spasms had lower mean serum vitamin B12 levels (354.1 pg/mL; standard deviation 234.1 pg/mL) as compared to children with global developmental delay without spasms (466.7 pg/mL; standard deviation 285.5 pg/mL) ( P value < .05). Mean serum homocysteine level (13.9 vs 7.8 µmol/L, P = .02) and mean urinary methylmalonic acid level (68.1 mmol/mol of creatinine vs 26.1 mmol/mol of creatinine, P = .03) were elevated in children with infantile spasms than in controls. Fourteen children (35.0%) with infantile spasms were vitamin B12 deficient compared with 3 (7.50%) controls ( P = .005). Thus, vitamin B12 deficiency may have an association with infantile spasms. More studies are needed before recommending routine measurement of serum B12 levels in children with infantile spasms.

Neonatal intensive care unit phthalate exposure and preterm infant neurobehavioral performance.

Every year in the United States, more than 300,000 infants are admitted to neonatal intensive care units (NICU) where they are exposed to a chemical-intensive hospital environment during a developmentally vulnerable period. The neurodevelopmental impact of environmental exposure to phthalates during the NICU stay is unknown. As phthalate exposure during the third trimester developmental window has been implicated in neurobehavioral deficits in term-born children that are strikingly similar to a phenotype of neurobehavioral morbidity common among children born premature, the role of early-life phthalate exposure on the neurodevelopmental trajectory of premature infants may be clinically important. In this study, premature newborns with birth weight <1500g were recruited to participate in a prospective environmental health cohort study, NICU-HEALTH (Hospital Exposures and Long-Term Health), part of the DINE (Developmental Impact of NICU Exposures) cohort of the ECHO (Environmental influences on Child Health Outcomes) program. Seventy-six percent of eligible infants enrolled in the study. Sixty-four of 81 infants survived and are included in this analysis. 164 urine specimens were analyzed for phthalate metabolites using high-performance liquid chromatography/tandem mass spectrometry. The NICU Network Neurobehavioral Scale (NNNS) was performed prior to NICU discharge. Linear and weighted quantile sum regression quantified associations between phthalate biomarkers and NNNS performance, and between phthalate biomarkers and intensity of medical intervention. The sum of di(2-ethylhexyl) phthalate metabolites (∑DEHP) was associated with improved performance on the Attention and Regulation scales. Specific mixtures of phthalate biomarkers were also associated with improved NNNS performance. More intense medical intervention was associated with higher ∑DEHP exposure. NICU-based exposure to phthalates mixtures was associated with improved attention and social response. This suggests that the impact of phthalate exposure on neurodevelopment may follow a non-linear trajectory, perhaps accelerating the development of certain neural networks. The long-term neurodevelopmental impact of NICU-based phthalate exposure needs to be evaluated.

Laboratory diagnosis of creatine deficiency syndromes: a technical standard and guideline of the American College of Medical Genetics and Genomics.

Disclaimer: These ACMG Standards and Guidelines are intended as an educational resource for clinical laboratory geneticists to help them provide quality clinical laboratory genetic services. Adherence to these standards and guidelines is voluntary and does not necessarily assure a successful medical outcome. These Standards and Guidelines should not be considered inclusive of all proper procedures and tests or exclusive of others that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, clinical laboratory geneticists should apply their professional judgment to the specific circumstances presented by the patient or specimen. Clinical laboratory geneticists are encouraged to document in the patient's record the rationale for the use of a particular procedure or test, whether or not it is in conformance with these Standards and Guidelines. They also are advised to take notice of the date any particular guideline was adopted, and to consider other relevant medical and scientific information that becomes available after that date. It also would be prudent to consider whether intellectual property interests may restrict the performance of certain tests and other procedures.Cerebral creatine deficiency syndromes are neurometabolic conditions characterized by intellectual disability, seizures, speech delay, and behavioral abnormalities. Several laboratory methods are available for preliminary and confirmatory diagnosis of these conditions, including measurement of creatine and related metabolites in biofluids using liquid chromatography-tandem mass spectrometry or gas chromatography-mass spectrometry, enzyme activity assays in cultured cells, and DNA sequence analysis. These guidelines are intended to standardize these procedures to help optimize the diagnosis of creatine deficiency syndromes. While biochemical methods are emphasized, considerations for confirmatory molecular testing are also discussed, along with variables that influence test results and interpretation.Genet Med 19 2, 256-263.

Creatine Transporter Deficiency: Screening of Males with Neurodevelopmental Disorders and Neurocognitive Characterization of a Case.

OBJECTIVE: Creatine transporter deficiency (CTD) is an X-linked, neurometabolic disorder associated with intellectual disability that is characterized by brain creatine (Cr) deficiency and caused by mutations in SLC6A8, the Cr transporter 1 protein gene. CTD is identified by elevated urine creatine/creatinine (Cr/Crn) ratio or reduced Cr peak on brain magnetic resonance spectroscopy; the diagnosis is confirmed by decreased Cr uptake in cultured fibroblasts, and/or identification of a mutation in the SLC6A8 gene. Prevalence studies suggest this disorder may be underdiagnosed. We sought to identify cases from a well-characterized cohort of children diagnosed with neurodevelopmental disorders. METHOD: Urine screening for CTD was performed on a cohort of 46 males with autism spectrum disorder (ASD) and 9 males with a history of non-ASD developmental delay (DD) classified with intellectual disability. RESULTS: We identified 1 patient with CTD in the cohort based on abnormal urine Cr/Crn, and confirmed the diagnosis by the identification of a novel frameshift mutation in the SLC6A8 gene. This patient presented without ASD but with intellectual disability, and was characterized by a nonspecific phenotype of early language delay and DD that persisted into moderate-to-severe intellectual disability, consistent with previous descriptions of CTD. CONCLUSION: Identification of patients with CTD is possible by measuring urine Cr and Crn levels and the current case adds to the growing literature of neurocognitive deficits associated with the disorder that affect cognition, language and behavior in childhood.

Succinic semialdehyde dehydrogenase deficiency of four Chinese patients and prenatal diagnosis for three fetuses.

Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare autosomal recessive disorder that affects the degradation of γ-aminobutyric acid (GABA). Only a few cases of SSADH deficiency have been documented in mainland China and prenatal diagnosis has not been performed. SSADH deficiency in four patients (three girls and one boy) from four unrelated Chinese families was detected by selective screening at the age of 50days to 1year. Four patients were admitted due to intractable seizures and psychomotor retardation. Their urine 4-hydroxybutyric acid was significantly elevated. Seven mutations in their ALDH5A1 gene were identified, of which the following six were novel: c.127-128insGGCCC (p.Q43Rfs*50), [corrected] c.615delT (p.F206Sfs*5), c.1313T>C (p.L438P), c.1568C>T (p.S523F), 1383-2delA and a 0.15-Mb deletion harboring ALDH5A1. Only one mutation, c.820C>T, had been previously reported. Three mothers of Patients 1-3 underwent amniocentesis during their third pregnancy and the fetuses were not affected by SSADH deficiency. Normal development and urine organic acid levels of the infants confirmed the prenatal diagnosis after birth.

Arsenic methylation capacity and developmental delay in preschool children in Taiwan.

Environmental exposure to lead or mercury can cause neurodevelopmental damage. Arsenic is another neurotoxicant that can affect intellectual function in children. This study was designed to explore the difference of arsenic methylation capacity indices between with and without developmental delay in preschool children. We also aimed to identify whether blood levels of lead or mercury modify the effect of arsenic methylation capacity indices. A cross sectional study was conducted from August 2010 to March 2012. All participants recruited from the Shin Kong Wu Ho-Su Memorial Teaching Hospital. In all, 63 children with developmental delay and 35 children without developmental delay were recruited. Urinary arsenic species, including arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA(V)) and dimethylarsinic acid (DMA(V)) were measured with a high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Lead and mercury levels of red blood cells were measured by inductively coupled mass spectrometry. All participants underwent developmental assessments to confirm developmental delays, including evaluations of gross motor, fine motor, speech-language, cognition, social, and emotional domains. Urinary total arsenic and MMA(V) percentage were significantly positively associated and DMA(V) percentage was negatively associated with the risk of developmental delay in a dose-dependent manner after adjustment for blood lead or mercury levels and other risk factors. A multivariate regression analysis indicated that blood lead level and arsenic methylation capacity each independently contributed to the risk of developmental delay. This is the first study to show that arsenic methylation capacity is associated with developmental delay, even without obvious environmental arsenic exposure.

Child Neurology: cognitive delay in a 7-year-old girl.

Organic acidurias are an important group of inherited metabolic disorders that affect the intermediary metabolic pathways of carbohydrate, amino acid, and fatty acid oxidation, leading to the accumulation of organic acids.(1) The 2-hydroxyglutaric acidurias are rare neurometabolic disorders characterized by developmental delay with or without other neurologic dysfunction. Three different subtypes have been described: d-2-hydroxyglutaric aciduria, l-2-hydroxyglutaric aciduria, and combined d-l-2-hydroxyglutaric aciduria. We describe the case of a child presenting with developmental delay who was found to have the classical biochemical, imaging, and genetic features of l-2-hydroxyglutaric aciduria.

Pyridoxine-dependent epilepsy with elevated urinary α-amino adipic semialdehyde in molybdenum cofactor deficiency.

α-Amino adipic semialdehyde (α-AASA) accumulates in body fluids from patients with pyridoxine-dependent epilepsy because of mutations in antiquitin (ALDH7A1) and serves as the biomarker for this condition. We have recently found that the urinary excretion of α-AASA was also increased in molybdenum cofactor and sulfite oxidase deficiencies. The seizures in pyridoxine-dependent epilepsy are caused by lowered cerebral levels of pyridoxal-5-phosphate (PLP), the bioactive form of pyridoxine (vitamin B(6)), which can be corrected by the supplementation of pyridoxine. The nonenzymatic trapping of PLP by the cyclic form of α-AASA is causative for the lowered cerebral PLP levels. We describe 2 siblings with clinically evident pyridoxine-responsive seizures associated with increased urinary excretion of α-AASA. Subsequent metabolic investigations revealed several metabolic abnormities, all indicative for molybdenum cofactor deficiency. Molecular investigations indeed revealed a known homozygous mutation in the MOCS2 gene. Based upon the clinically evident pyridoxine-responsive seizures in these 2 siblings, we recommend considering pyridoxine supplementation to patients affected with molybdenum cofactor or sulfite oxidase deficiencies.

Oxidative stress in developmental brain disorders.

In order to examine the involvement of oxidative stress in developmental brain disorders, we have performed immunohistochemistry in autopsy brains and enzyme-linked immunosorbent assay (ELISA) in the cerebrospinal fluid and urines of patients. Here, we review our data on the hereditary DNA repair disorders, congenital metabolic errors and childhood-onset neurodegenerative disorders. First, in our studies on hereditary DNA repair disorders, increased oxidative DNA damage and lipid peroxidation were carried out in the degeneration of basal ganglia, intracerebral calcification and cerebellar degeneration in patients with xeroderma pigmentosum, Cockayne syndrome and ataxia-telangiectasia-like disorder, respectively. Next, congenital metabolic errors, apoptosis due to lipid peroxidation seemed to cause neuronal damage in neuronal ceroid-lipofuscinosis. Oxidative stress of DNA combined with reduced expression of antioxidant enzymes occurred in the lesion of the cerebral cortex in mucopolysaccharidoses and mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes. In childhood-onset neurodegenerative disorders, increased oxidative DNA damage and lipid peroxidation may lead to motor neuron death in spinal muscular atrophy like in amyotrophic lateral sclerosis. In patients with dentatorubral-pallidoluysian atrophy, a triplet repeat disease, deposition of oxidative products of nucleosides and reduced expression of antioxidant enzymes were found in the lenticular nucleus. In contrast, the involvement of oxidative stress is not definite in patients with Lafora disease. Rett syndrome patients showed changes of oxidative stress markers and antioxidant power in urines, although the changes may be related to systemic complications.

Evaluation of urinary S100B protein level and lactate/creatinine ratio for early diagnosis and prognostic prediction of neonatal hypoxic-ischemic encephalopathy.

BACKGROUND: Early identification and prevention of hypoxic-ischemic encephalopathy (HIE) in newborns may reduce neonatal mortality and neurological dysfunction. OBJECTIVE: To analyze the diagnostic and prognostic values of urinary S100B level and lactate/creatinine ratio in newborns with HIE. METHODS: Seventy-eight full-term newborns with HIE and 25 normal newborns were enrolled. The Neonatal Behavioral Neurological Assessment (NBNA) and Developmental Screening Test were scored. The concentration of urinary S100B protein was determined using the S100B enzyme-linked immunosorbent assay and the levels of urinary lactate and creatinine were measured with the enzyme colorimetric method. RESULTS: Urinary S100B level on days 1-3 after birth and lactate/creatinine ratio on day 1 were significantly higher in newborns with HIE than those in the control group. Both indexes were positively correlated with the clinical grading of HIE. A cutoff value for the S100B level of 0.47 microg/l on day 3 after birth had a sensitivity of 90% and specificity of 92% for prediction of HIE. A lactate/creatinine ratio of more than 0.55 on day 1 showed the highest sensitivity (92%) and specificity (90%). A combination of both indexes improved the sensitivity and specificity to 99 and 97%, respectively. A negative correlation of both lactate/creatinine ratio on day 1 and S100B level on days 1-3 after birth with the NBNA score was identified on days 3, 7 and 14 after birth. The Developmental Screening Test score of 36 newborns with HIE within 6 months after birth showed that 65% of infants with moderate and high HIE had an abnormal developmental quotient. CONCLUSION: These data suggest that early measurement of both S100B level and lactate/creatinine ratio in the urine of newborns with HIE is a practical convenient and sensitive way to improve diagnosis on the third day of life and prognostic prediction of HIE.

Severe infantile hypotonia with ethylmalonic aciduria: case report.

An 8-month-old girl was admitted to an outpatient clinic with significant hypotonia and weakness. Organic acid analysis in urine revealed a significant increase in ethylmalonic acid. A deoxyribonucleic analysis revealed the presence of a 625G>A (G-to-A substitution at nucleotide 625) variant short-chain acyl-coenzyme A dehydrogenase gene polymorphism. With the clinical, biochemical and molecular findings, short-chain acyl-coenzyme A dehydrogenase deficiency was suspected. Because 625G>A and 511C>T (C-to-T substitution at nucleotide 511) genetic variations are also present in 14% of the general population, these are considered to be genetic sensitivity variations rather than causing a disease themselves and to result in possible short-chain acyl-coenzyme A dehydrogenase deficiency in the presence of environmental factors such as fever and hunger as well as cellular, biochemical, and other genetic factors. It was stressed that severe infantile hypotonia could also be the only manifestation of ethylmalonic aciduria spectrum disorders.

Urine amino and organic acids analysis in developmental delay or intellectual disability.

OBJECTIVES: To determine the proportion of urine amino and organic acids screening tests (UMS) undertaken for patients referred with developmental delay or intellectual disability (DD/ID), and within the group with DD/ID, to determine the diagnostic yield, the proportion of diagnoses with a therapy and the associated recurrence risks. METHODS: A retrospective review of request forms and results of UMS, in individuals older than 28 days, referred to the Women's and Children's Hospital, North Adelaide, between 1 January 1992 and 31 December 1998 was carried out. Urine was analysed by ion exchange chromatography (amino acids), gas chromatography/mass spectrometry (organic acids), colorimetric assay (orotic acid) and stable isotope-dilution mass spectrometry (trimethylamine). RESULTS: A total of 3316 samples were received, 1447 being from patients with DD/ID. A diagnosis was determined for 1.8% of all referrals. For patients with DD/ID, the diagnostic yield was 1.1%, with a similar yield for isolated DD/ID and DD/ID with other features (9/828 vs 7/619; chi2 = 0.006; P = 0.93). Specific therapies were available for 69% of diagnoses associated with DD/ID and 87.5% had known Mendelian or mitochondrial inheritance. CONCLUSION: Urine metabolic screening is an important part of the evaluation of children with DD/ID as it can enable families to make reproductive decisions and children to receive appropriate therapy early.

Dominant inheritance of sialuria, an inborn error of feedback inhibition.

"French type" sialuria, a presumably dominant disorder that, until now, had been documented in only five patients, manifests with mildly coarse facies, slight motor delay, and urinary excretion of large quantities (>1 g/d) of free N-acetylneuraminic acid (NeuAc). The basic defect consists of the very rare occurrence of failed feedback inhibition of a rate-limiting enzyme, in this case uridinediphosphate-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase, by a downstream product, in this case cytidine monophosphate (CMP)-NeuAc. We report a new patient with sialuria who has a heterozygous G-->A substitution in nucleotide 848 of the epimerase gene, which results in an R266Q change. The proband's other allele, as expected, had no mutation. However, the heterozygous R266Q mutation was detected in the patient's mother, who has similarly increased urinary levels of free NeuAc, thereby confirming, for the first time, the dominant mode of inheritance of this inborn error. The biochemical diagnosis of the proband was verified by the greatly increased level of free NeuAc in his cultured fibroblasts, the NeuAc distribution, mainly (59%) in the cytoplasm, and by the complete failure of 100 microM CMP-NeuAc to inhibit UDP-GlcNAc 2-epimerase activity in the mutant cells. These findings call for expansion of the phenotype to include adults and for more-extensive assaying of free NeuAc in the urine of children with mild developmental delay. The prevalence of sialuria is probably grossly underestimated.

Methylmalonic semialdehyde dehydrogenase deficiency: psychomotor delay and methylmalonic aciduria without metabolic decompensation.

A patient presenting with developmental delay but no episodes of metabolic acidosis was found to excrete significant amounts of methylmalonate (MMA) without any associated increased excretion of malonate, ethylmalonate, 3-hydroxypropionate, or beta-alanine. In contrast to patients with methylmalonic aciduria due to deficient mutase or impaired cobalamin metabolism, there was no increase of propionylcarnitine in blood or urine. The activity of methylmalonyl-CoA mutase and the pathway for cobalamin metabolism were also intact. The quantitative levels of the various labeled enantiomers of 3-hydroxyisobutyric (3-HIBA), 3-aminoisobutyric (3-AIBA), MMA, and propionylcarnitine were compared following separate intravenous infusions of equimolar doses of [2H8]-valine or [2H4]thymine in this patient and another with methylmalonyl-CoA mutase deficiency. Levels of labeled S- and R-3-HIBA and S- and R-3-AIBA indicated an isolated defect in methylmalonic semialdehyde dehydrogenase in this patient. This condition can be recognized by plasma MMA levels of approximately 8.5 microM (cf. 400 microM in mutase deficiency), urine MMA of 20-55 micromol/kg/24 h (cf. 1150 micromol/kg/24 h), no increase in propionylcarnitine following an oral carnitine load, and increased excretion of S-3-AIBA-nearly 10 times that observed in mutase deficiency. The ratio of R-AIBA to S-AIBA of <1 also reflects this disorder.

A new case of malonyl coenzyme A decarboxylase deficiency presenting with cardiomyopathy.

UNLABELLED: A new case of mitochondrial malonyl coenzyme A decarboxylase deficiency is described. The patient presented with an initial episode of metabolic acidosis, seizures, hypoglycemia, and cardiac failure at 2 months of age which slowly resolved. Subsequent evaluations at 4 years of age for developmental delay revealed a prominent elevation of malonic acid in urine. Malonyl carnitine was also elevated. The activity of Malonyl CoA decarboxylase in cultured fibroblasts was 7% of normal. CONCLUSION: Malonyl CoA decarboxylase deficiency may result in inhibition of fatty acid oxidation, which may account for the cardiomyopathy.

D-2-hydroxyglutaric aciduria in neonate with seizures and CNS dysfunction.

D-2-Hydroxyglutaric aciduria was documented in a newborn who presented with seizures, hypotonia, cortical blindness, a movement disorder, and developmental delay. Her clinical presentation differs from that of patients with L-2-hydroxyglutaric aciduria and a single previously reported patient with D-2-hydroxyglutaric aciduria. Cerebrospinal fluid levels of gamma-aminobutyric acid were elevated, while biogenic amine metabolites were normal. The movement disorder in our patient and in those with L-2-hydroxyglutaric aciduria suggests involvement of the basal ganglia in the disease process. Prenatal diagnosis of an affected fetus was accomplished during a subsequent pregnancy.

Maternal phenylketonuria.

A mother with phenylketonuria and hyperphenylalaninaemia of 960 mumol/L with four intellectually deficient offspring is described. In addition a mother with hyperphenylalaninaemia of 2100 mumol/L and two intellectually deficient microcephalic children is described. None of the affected children exhibited elevations of blood phenylalanine. In utero phenylalanine toxicity was considered a factor causing the handicaps.