Expanding Phenotypic Spectrum of Cerebral Aspartate-Glutamate Carrier Isoform 1 (AGC1) Deficiency.

CASE: We are reporting the third unrelated case of cerebral aspartate-glutamate carrier isoform 1 (AGC1) deficiency. Patient is a 21-month-old Yemeni male who presented with refractory seizure disorder and developmental arrest. Neuroimaging showed cerebral volume loss and diminished N-acetylaspartate (NAA) peak. Whole exome sequencing revealed a homozygous novel missense variant in the SLC25A12 gene. Patient's seizure frequency abated drastically following initiation of ketogenic diet. DISCUSSION AND CONCLUSION: Cerebral AGC1 deficiency results in dysfunction of mitochondrial malate aspartate shuttle, thereby prohibiting myelin synthesis. There are significant phenotypic commonalities between our patient and previously reported cases including intractable epilepsy, psychomotor delay, cerebral atrophy, and diminished NAA peak. Our report also provides evidence regarding beneficial effect of ketogenic diet in this rare neurometabolic epilepsy.

Disturbed phospholipid metabolism in serine biosynthesis defects revealed by metabolomic profiling.

Serine biosynthesis defects are autosomal recessive metabolic disorders resulting from the deficiency of any of the three enzymes involved in de novo serine biosynthesis, specifically phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). In this study, we performed metabolomic profiling on 4 children with serine biosynthesis defects; 3 with PGDH deficiency and 1 with PSAT deficiency. The evaluations were performed at baseline and with serine and glycine supplementation. Metabolomic profiling performed at baseline showed low phospholipid species, including glycerophosphocholine, glycerophosphoethanolamine, and sphingomyelin. All children had low serine and glycine as expected. Low glycerophosphocholine compounds were found in 4 children, low glycerophosphoethanolamine compounds in 3 children, and low sphingomyelin species in 2 children. Metabolic profiling with serine and glycine supplementation showed normalization of most of the low phospholipid compounds in the 4 children. Phospholipids are the major component of plasma and intracellular membranes, and phosphatidylcholine is the most abundant phospholipid of all mammalian cell types and subcellular organelles. Phosphatidylcholine is of particular importance for the nervous system, where it is essential for neuronal differentiation. The observed low phosphatidylcholine species in children with serine biosynthesis defects that improved after serine supplementation, supports the role of serine as a significant precursor for phosphatidylcholine. The vital role that phosphatidylcholine has during neuronal differentiation and the pronounced neurological manifestations in serine biosynthesis defects suggest that phosphatidylcholine deficiency occurring secondary to serine deficiency may have a significant contribution to the development of the neurological manifestations in individuals with serine biosynthesis defects.

Inhibitory Basal Ganglia Inputs Induce Excitatory Motor Signals in the Thalamus.

Basal ganglia (BG) circuits orchestrate complex motor behaviors predominantly via inhibitory synaptic outputs. Although these inhibitory BG outputs are known to reduce the excitability of postsynaptic target neurons, precisely how this change impairs motor performance remains poorly understood. Here, we show that optogenetic photostimulation of inhibitory BG inputs from the globus pallidus induces a surge of action potentials in the ventrolateral thalamic (VL) neurons and muscle contractions during the post-inhibitory period. Reduction of the neuronal population with this post-inhibitory rebound firing by knockout of T-type Ca2+ channels or photoinhibition abolishes multiple motor responses induced by the inhibitory BG input. In a low dopamine state, the number of VL neurons showing post-inhibitory firing increases, while reducing the number of active VL neurons via photoinhibition of BG input, effectively prevents Parkinson disease (PD)-like motor symptoms. Thus, BG inhibitory input generates excitatory motor signals in the thalamus and, in excess, promotes PD-like motor abnormalities. VIDEO ABSTRACT.

The ketogenic diet compensates for AGC1 deficiency and improves myelination.

The brain aspartate-glutamate carrier (AGC1) is specifically expressed in neurons, where it transports aspartate from the mitochondria to the cytosol, and plays a role in transfer of nicotinamide adenine dinucleotide (NADH)-reducing equivalents into the mitochondria as a part of the malate-aspartate shuttle. Deficient function of AGC1 underlies an inborn error of metabolism that presents with severe hypotonia, arrested psychomotor development, and seizures from a few months of age. In AGC1 deficiency, there is secondary hypomyelination due to lack of N-acetylaspartate (NAA), which is normally generated by acetylation of aspartate in the neuron and required for fatty acid synthesis by the adjacent oligodendrocyte. Based on experiences from AGC2 deficiency, we predicted that reduced glycolysis should compensate for the metabolic defect and allow resumed myelination in AGC1 deficiency. Carbohydrate restriction was therefore initiated in a patient with AGC1 deficiency at 6 years of age by introducing a ketogenic diet. The response was dramatic, clinically as well as radiologically. Psychomotor development showed clear improvement, and magnetic resonance imaging (MRI) indicated resumed myelination. This is the first successful treatment of secondary hypomyelination reported. Because AGC1 is driven by the proton gradient generated by the neuronal mitochondrial respiratory chain, the results have potential relevance for secondary hypomyelination in general.

Effects of dietary creatine supplementation for 8 weeks on neuromuscular coordination and learning in male albino mouse following neonatal hypoxic ischemic insult.

Creatine monohydrate (Cr) is a dietary supplement known to improve cognitive functions and has positive therapeutic results under various clinical conditions. The aim of this study was to determine the effect of 2 % Cr supplementation on learning, memory formation, neuromuscular coordination, exploratory and locomotory in male albino mice following hypoxic ischemic insult. At postnatal day, 10 male albino mice pups were subjected to right common carotid artery ligation followed by 8 % hypoxia for 25 min. On postnatal day 20, male mice were separated from the litter and divided into two groups on the basis of special diet supplementation. One group was supplemented with 2 % Cr in diet while the other group was raised on ordinary rodent chow for 8 weeks. Behavioral observations were made during rota rod, open field and Morris water maze test for both treatments. It was observed that supplementation with 2 % Cr for 8 weeks following neonatal brain damage resulted in enhanced muscular strength, neuromuscular coordination and improved body weight. In Morris water maze test, it was observed that Cr supplementation significantly improved mean swimming speed and mice on 2 % Cr diet covered more distance but the spatial memory was not improved significantly following hypoxia ischemia encephalopathy (HIE). Open field parameters and percentage of infarct volume remained unaffected following Cr supplementation. We concluded that 2 % dietary Cr supplementation has a potential to improve the muscle strength and body weight in male albino mice following (HIE) and should be considered for the treatment of neurological ailments.

Mild fumarase deficiency and a trial of low protein diet.

We report clinical findings in a 12-year-old girl with a mild case of fumarase deficiency who continues to make progress. She has two novel mutations of the fumarase gene [c.521C>G (p.P174R) and c.908T>C (p.L303S)]. A trial of low protein diet did not reduce fumaric aciduria.

Supplementation with antioxidants and folinic acid for children with Down's syndrome: randomised controlled trial.

OBJECTIVES: To assess whether supplementation with antioxidants, folinic acid, or both improves the psychomotor and language development of children with Down's syndrome. DESIGN: Randomised controlled trial with two by two factorial design. SETTING: Children living in the Midlands, Greater London, and the south west of England. PARTICIPANTS: 156 infants aged under 7 months with trisomy 21. INTERVENTION: Daily oral supplementation with antioxidants (selenium 10 mug, zinc 5 mg, vitamin A 0.9 mg, vitamin E 100 mg, and vitamin C 50 mg), folinic acid (0.1 mg), antioxidants and folinic acid combined, or placebo. MAIN OUTCOME MEASURES: Griffiths developmental quotient and an adapted MacArthur communicative development inventory 18 months after starting supplementation; biochemical markers in blood and urine at age 12 months. RESULTS: Children randomised to antioxidant supplements attained similar developmental outcomes to those without antioxidants (mean Griffiths developmental quotient 57.3 v 56.1; adjusted mean difference 1.2 points, 95% confidence interval -2.2 to 4.6). Comparison of children randomised to folinic acid supplements or no folinic acid also showed no significant differences in Griffiths developmental quotient (mean 57.6 v 55.9; adjusted mean difference 1.7, -1.7 to 5.1). No between group differences were seen in the mean numbers of words said or signed: for antioxidants versus none the ratio of means was 0.85 (95% confidence interval 0.6 to 1.2), and for folinic acid versus none it was 1.24 (0.87 to 1.77). No significant differences were found between any of the groups in the biochemical outcomes measured. Adjustment for potential confounders did not appreciably change the results. CONCLUSIONS: This study provides no evidence to support the use of antioxidant or folinic acid supplements in children with Down's syndrome. TRIAL REGISTRATION: Clinical trials NCT00378456.

Perinatal choline supplementation does not mitigate motor coordination deficits associated with neonatal alcohol exposure in rats.

Prenatal alcohol exposure can disrupt brain development, leading to a variety of behavioral alterations including learning deficits, hyperactivity, and motor dysfunction. We have been investigating the possibility that perinatal choline supplementation may effectively reduce the severity of alcohol's adverse effects on behavioral development. We previously reported that perinatal choline supplementation can ameliorate alcohol-induced learning deficits and hyperactivity in rats exposed to alcohol during development. The present study examined whether perinatal choline supplementation could also reduce the severity of motor deficits induced by alcohol exposure during the third trimester equivalent brain growth spurt. Male neonatal rats were assigned to one of three treatment groups. One group was exposed to alcohol (6.6 g/kg/day) from postnatal days (PD) 4 to 9 via an artificial rearing procedure. Artificially and normally reared control groups were included. One half of subjects from each treatment received daily subcutaneous injections of a choline chloride solution from PD 4 to 30, whereas the other half received saline vehicle injections. On PD 35-37, subjects were tested on a parallel bar motor task, which requires both balance and fine motor coordination. Ethanol-exposed subjects exhibited significant motor impairments compared to both control groups whose performance did not differ significantly from one another. Perinatal choline treatment did not affect motor performance in either ethanol or control subjects. These data indicate that the beneficial effects of perinatal choline supplementation in ethanol-treated subjects are task specific and suggest that choline is more effective in mitigating cognitive deficits compared to motor deficits associated with developmental alcohol exposure.

Valoración del estado nutricional en niños y adolescentes con trastorno psicomotor / Evaluation of the nutritional state in children and teen-agers with psychomotrical troubles

Si en cualquier paciente es importante la valoración de su estado nutricional, ésta se hace imprescindible en niños y adolescentes con Trastorno Psicomotor. Se sabe que un déficit de energía, proteínas y micronutrientes, interfiere con el crecimiento, desarrollo y función neuromuscular de niños y adolescentes sanos. En los que padecen trastorno psicomotor es mayor el riesgo de presentar estos déficits, lo cual se convierte en factor de agresión añadido a su estado general que puede tener graves consecuencias. Por su importancia e interés clínico en beneficio de los pacientes con trastorno psicomotor, se presenta este planteamiento de Evaluación Nutricional, que si bien tiene como base los valores estándar para individuos sanos, de edad y sexo similares, aporta algunas especificaciones útiles para la valoración de quienes presentan trastorno psicomotor. Esta evaluación será provechosa, siempre que se realice de modo sistemático y con una periodicidad determinada (AU)