Does ketogenic diet improve cognitive function in patients with GLUT1-DS? A 6- to 17-month follow-up study

Novel insight into GLUT1 deficiency syndrome: screening for emotional and behavioral problems in youths following ketogenic diet

BACKGROUND

Glucose transporter type 1 deficiency syndrome (GLUT1DS) is a rare disorder with a broad spectrum of neurological manifestations. The ketogenic diet (KD) is, to date, the gold standard treatment. Behavioral problems, well recognized in patients with chronic conditions, have not been, so far, deeply investigated in GLUT1DS patients. We performed an exploratory study to assess the risk of emotional and behavioral problems and investigated the potential role of influencing factors related to the pathology itself or KD treatment.

METHODS

This was a mono-center retrospective study involving youths with GLUT1Ds treated with KD and a group of migraine patients age- and gender-matched. Patients were included if the main caregiver completed the Child Behavior Check List 6-18 (CBCL). Descriptive statistics for demographic and clinical data and questionnaire scores were computed. Correlational analyses were used to assess the potential associations of clinical variables and age and time from KD introduction with CBCL scores in GLUT1DS patients.

RESULTS

We enrolled nine youths with GLUT1DS and 9 with migraine. In the GLUT1DS group, none of the mean scores of the CBCL items fell within the borderline/clinical range, except for social problems located in the borderline range. Investigation for influencing factors revealed the patient's age related to withdrawn/depressive (r=0.709, P=0.032) and social problems (r=.684, P=0.042). Time from the introduction of KD was related to social problems (r=.827, P=0.006). From the comparison with the scores obtained from migraine patients, significantly higher scores emerged in the latter group in internalizing problems (Z=-2.48, P=0.01), externalizing problems (Z=-3.49, P<0.001), anxious/depressed subscale (Z=-2.37, P=0.014), somatic complaints subscale (Z=-2.624, P=0.008), aggressive behavior subscale (Z=-2.539, P=0.011).

CONCLUSIONS

Although highly exploratory in its nature, this study provides a novel insight into GLUT1DS. Our data suggested that the risk for internalizing problems in GLUT1DS youths was related to higher age and higher time elapsed from KD introduction. They occurred at a sub-clinical level, making them difficult to detect, if not expressly and systematically investigated.

Effects of the ketogenic diet on cognition: a systematic review

INTRODUCTION

Ketogenic diet (KD) therapy has been used as a dietary intervention in drug-resistant epilepsy for several years. Research currently suggests that KD therapy may carry neuroprotective and cognition enhancing effects for individuals with non-epileptic conditions as well as for healthy individuals. Therefore, KD may have potential as a non-invasive, nutritional treatment approach for difficult to manage conditions such as neurodegenerative illnesses or mood disorders. The aim of this review is to summarize the available evidence on ketogenic interventions and the resulting cognitive outcomes.

MATERIALS AND METHODS

The paper was based on PRISMA 2020 guidelines. The search was conducted in June 2021 on the following databases: CENTRAL, PubMed, EMBASE, PsycInfo, Web of Science. The search yielded 2014 studies, of which 49 were included.

RESULTS

There were 22 animal studies assessing murine models and 27 studies on humans. The primary indications in these studies were epileptic conditions, neurodegenerative disorders, cognitive impairment, and healthy populations.

DISCUSSION

Administration of KD seems to confer cognitive-enhancing effects in areas such as working memory, reference memory and attention. Studies found that KD treatment in animals has the potential to alleviate age-related cognitive decline. Over 80% of the 27 human studies reported a favourable effect of intervention, and none reported a detrimental effect of KD. While these findings suggest that KD may improve the functioning of certain cognitive domains, definitive conclusions were limited by studies with small sample sizes, the absence of controls and randomization, and the lack of objective measures of cognition.

Nutritional Intervention Through Ketogenic Diet in GLUT1 Deficiency Syndrome

Glucose transporter type 1 (GLUT1) deficiency syndrome (DS) is a metabolic brain disorder caused by a deficiency resulting from SLC2A1 gene mutation and is characterized by abnormal brain metabolism and associated metabolic encephalopathy. Reduced glucose supply to the brain leads to brain damage, resulting in delayed neurodevelopment in infancy and symptoms such as eye abnormalities, microcephaly, ataxia, and rigidity. Treatment options for GLUT1 DS include ketogenic diet (KD), pharmacotherapy, and rehabilitation therapy. Of these, KD is an essential and the most important treatment method as it promotes brain neurodevelopment by generating ketone bodies to produce energy. This case is a focused study on intensive KD nutritional intervention for an infant diagnosed with GLUT1 DS at Gangnam Severance Hospital from May 2022 to January 2023. During the initial hospitalization, nutritional intervention was performed to address poor intake via the use of concentrated formula and an attempt was made to introduce complementary feeding. After the second hospitalization and diagnosis of GLUT1 DS, positive effects on the infant's growth and development, nutritional status, and seizure control were achieved with minimal side effects by implementing KD nutritional intervention and adjusting the type and dosage of anticonvulsant medications. In conclusion, for patients with GLUT1 DS, it is important to implement a KD with an appropriate ratio of ketogenic to nonketogenic components to supply adequate energy. Furthermore, individualized and intensive nutritional management is necessary to improve growth, development, and nutritional status.

Timing of Ketogenic Dietary Therapy (KDT) Introduction and Its Impact on Cognitive Profiles in Children with Glut1-DS—A Preliminary Study

The aim of this research was to characterize cognitive abilities in patients with Glut1-Deficiency syndrome (Glut1DS) following ketogenic diet therapy (KDT). Methods: The cognitive profiles of eight children were assessed using the Wechsler Intelligence Scale (WISC-IV). The effect of ketogenic diet therapy (KDT) on individual subareas of intelligence was analyzed considering the potential influence of speech motor impairments. Results: Patients with Glut1DS showed a wide range of cognitive performance levels. Some participants showed statistically and clinically significant discrepancies between individual subdomains of intelligence. Both variables, KDT initiation as well as duration, had a positive effect on the overall IQ score. Significant correlations were partially found between the time of KDT initiation and the level of IQ scores, depending on the presence of expressive language test demands of the respective subtests of the WISC-IV. Accordingly, the participants benefited les in the linguistic cognitive domain. The discrepancies in cognitive performance profiles of patients with Glut1DS can be attributed to the possibility of a negative distortion of the results due to the influence of speech motor impairments. Conclusions: The individual access skills of test persons should be more strongly considered in test procedures for the assessment of intelligence to reduce the negative influence of motor deficits on test performance. Specific characterization and systematization of the speech disorder are indispensable for determining the severity of speech motor impairment in Glut1DS. Therefore, a stronger focus on dysarthria during diagnosis and therapy is necessary.

GLUT1-DS Italian registry: past, present, and future: a useful tool for rare disorders

BACKGROUND

GLUT1 deficiency syndrome is a rare, genetically determined neurological disorder for which Ketogenic Dietary Treatment represents the gold standard and lifelong treatment. Patient registries are powerful tools providing insights and real-world data on rare diseases.

OBJECTIVE

To describe the implementation of a national web-based registry for GLUT1-DS.

METHODS

This is a retrospective and prospective, multicenter, observational registry developed in collaboration with the Italian GLUT1-DS association and based on an innovative, flexible and configurable cloud computing technology platform, structured according to the most rigorous requirements for the management of patient's sensitive data. The Glut1 Registry collects baseline and follow-up data on the patient's demographics, history, symptoms, genotype, clinical, and instrumental evaluations and therapies.

RESULTS

Five Centers in Italy joined the registry, and two more Centers are currently joining. In the first two years of running, data from 67 patients (40 females and 27 males) have been collected. Age at symptom onset was within the first year of life in most (40, 60%) patients. The diagnosis was formulated in infancy in almost half of the cases (34, 51%). Symptoms at onset were mainly paroxysmal (mostly epileptic seizure and paroxysmal ocular movement disorder) or mixed paroxysmal and fixed symptoms (mostly psychomotor delay). Most patients (53, 79%) are currently under Ketogenic dietary treatments.

CONCLUSIONS

We describe the principles behind the design, development, and deployment of the web-based nationwide GLUT1-DS registry. It represents a stepping stone towards a more comprehensive understanding of the disease from onset to adulthood. It also represents a virtuous model from a technical, legal, and organizational point of view, thus representing a possible paradigmatic example for other rare disease registry implementation.

Emerging Role of the Ketogenic Dietary Therapies beyond Epilepsy in Child Neurology

Ketogenic dietary therapies (KDTs) have been in use for refractory paediatric epilepsy for a century now. Over time, KDTs themselves have undergone various modifications to improve tolerability and clinical feasibility, including the Modified Atkins diet (MAD), medium chain triglyceride (MCT) diet and the low glycaemic index treatment (LGIT). Animal and observational studies indicate numerous benefits of KDTs in paediatric neurological conditions apart from their evident benefits in childhood intractable epilepsy, including neurodevelopmental disorders such as autism spectrum disorder, rarer neurogenetic conditions such as Rett syndrome, Fragile X syndrome and Kabuki syndrome, neurodegenerative conditions such as Pelizaeus-Merzbacher disease, and other conditions such as stroke and migraine. A large proportion of the evidence is derived from individual case reports, case series and some small clinical trials, emphasising the vast scope for research in this avenue. The term 'neuroketotherapeutics' has been coined recently to encompass the rapid strides in this field. In the 100^th year of its use for paediatric epilepsy, this review covers the role of the KDTs in non-epilepsy neurological conditions among children.

GLUT1 Deficiency Syndrome-Early Treatment Maintains Cognitive Development? (Literature Review and Case Report)

Glucose transporter type 1 (GLUT1) is the most important energy carrier of the brain across the blood-brain barrier, and a genetic defect of GLUT1 is known as GLUT1 deficiency syndrome (GLUT1DS). It is characterized by early infantile seizures, developmental delay, microcephaly, ataxia, and various paroxysmal neurological phenomena. In most cases, GLUT1DS is caused by heterozygous single-nucleotide variants (SNVs) in the SLC2A1 gene that provoke complete or severe impairment of the functionality and/or expression of GLUT1 in the brain. Despite the rarity of these diseases, GLUT1DS is of high clinical interest since a very effective therapy, the ketogenic diet, can improve or reverse symptoms, especially if it is started as early as possible. We present a clinical phenotype, biochemical analysis, electroencephalographic and neuropsychological features of an 11-month-old boy with myoclonic seizures, hypogammaglobulinemia, and mildly impaired gross motor development. Using sequence analysis and deletion/duplication testing, deletion of an entire coding sequence in the SLC2A1 gene was detected. Early introduction of a modified Atkins diet maintained a seizure-free period without antiseizure medications and normal cognitive development in the follow-up period. Our report summarizes the clinical features of GLUT1 syndromes and discusses the importance of early identification and molecular confirmation of GLUT1DS as a treatable metabolic disorder.

Characterization of Speech and Language Phenotype in GLUT1DS

Background: To analyze the oral motor, speech and language phenotype in a sample of pediatric patients with GLUT 1 transporter deficiency syndrome (GLUT1DS). Methods: eight Italian-speaking children with GLUT1DS (aged 4.6–15.4 years) in stable treatment with ketogenic diet from a variable time underwent a specific and standardized speech and language assessment battery. Results: All patients showed deficits with different degrees of impairment in multiple speech and language areas. In particular, orofacial praxis, parallel and total movements were the most impaired in the oromotor domain; in the speech domain patients obtained a poor performance in the diadochokinesis rate and in the repetition of words that resulted as severely deficient in seven out of eight patients; in the language domain the most affected abilities were semantic/phonological fluency and receptive grammar. Conclusions: GLUT1DS is associated to different levels of speech and language impairment, which should guide diagnostic and therapeutic intervention. Larger population data are needed to identify more precisely a speech and language profile in GLUT1DS patients.

Ketogenic diet and cognition in neurological diseases: a systematic review

CONTEXT

In recent years, the ketogenic diet has gained special relevance as a possible therapeutic alternative to some neurological and chronic diseases.

OBJECTIVE

The aim of this systematic review was to answer the following question: Does a ketogenic diet improve cognitive skills in patients with Alzheimer's disease, Parkinson's disease, refractory epilepsy, and type 1 glucose deficiency syndrome? To define the research question, the PICOS criteria were used, following the guidelines of the PRISMA method.

DATA SOURCES

Medline/PubMed, Elsevier Science Direct, Dialnet, EBSCOhost, Mediagraphic, Sage Journals, ProQuest, and Wiley Online Library databases were used.

DATA EXTRACTION

After applying inclusion and exclusion criteria in accordance with the PRISMA method, a total of 63 entries published between 2004 and 2019 were used.

DATA ANALYSIS

The records extracted were analyzed from a qualitative approach, so no statistical analysis was carried out.

CONCLUSION

Although scientific literature on the subject is scarce and there has tended to be a lack of scientific rigor, the studies reviewed confirmed the effectiveness of this diet in improving the cognitive symptomatology of the aforementioned diseases.

Ketogenic diet for infants with epilepsy: A literature review

The ketogenic diet (KD) is an established, nonpharmacological treatment for drug-resistant epilepsy (DRE). Actually, KD and its variants have been shown to be elective and resolute for patients with glucose transporter type 1 (GLUT1) deficiency. The aim of this review was to study the use of KD and its variants in infancy, including the neonatal age, and demonstrate the safety and efficacy of this treatment in patients with the age of 0-23 months affected by DRE already subjected to pharmacological approach attempts. A literature search was conducted using PubMed as the medical database source. We used the age limit of 0-23 months, and we considered only articles published between the years 2015 and 2018, in light of increasing interest worldwide in the use of KD and its variants to manage DRE. We included 52 publications: 1 Cochrane study, 22 retrospective studies, 9 prospective studies, 4 randomized controlled trials (RCTs), 12 clinical cases, and 4 clinical reviews. Literature data showed that KD and its variants are safe and useful in patients with the age of 0-23 months with DRE. Classical KD is of first choice in the treatment of GLUT1 deficiency. Earlier introduction of KD in GLUT1 promises a better outcome and a decrease in seizure frequency in these patients.

Molecular diagnosis of epileptic encephalopathy of the first year of life applying a customized gene panel in a group of Argentinean patients

OBJECTIVE

The aim of this study was to perform a molecular characterization of 17 Argentinean pediatric patients with diagnosis of having epileptic encephalopathies (EEs) of the first year of life without known etiology, applying next-generation sequencing (NGS).

METHODS

We included 17 patients with EE with age of onset under 12 months without known etiology after ruling out structural abnormalities, metabolic disorders, and large chromosomal abnormalities. They presented with the following clinical phenotypes: Dravet syndrome (DS; n: 7), epilepsy of infancy with migrating focal seizures (EIMFS; n: 3), West syndrome (WS; n: 2), and undetermined epileptic encephalopathy (UEE; n: 5). Neurologic examinations, seizure semiology, brain magnetic resonance imaging, and standard electroencephalography (EEG) or video-EEG studies were performed in all cases. Using a custom amplicon strategy, we designed an NGS panel to study 47 genes associated with EEs.

RESULTS

Pathogenic variants were detected in 8 cases (47%), including seven novel pathogenic variants and one previously reported as being pathogenic. The pathogenic variants were identified in 6 patients with DS (SCN1A gene), one with EIMFS (SCN2A gene), and one with UEE (SLC2A1 gene). Nonrelevant variants were identified in the patients with WS.

CONCLUSION

We demonstrated the feasibility of an NGS-gene panel approach for the analysis of patients with EE in our setting. A genetic diagnosis was achieved in nearly 50% of patients, 87% of them presenting with nonpreviously reported variants. The early identification of the underlying causative genetic alteration will be a valuable tool for providing prognostic information and genetic counselling and also to improve therapeutic decisions in Argentinean patients.

A case report of glucose transporter 1 deficiency syndrome with growth hormone deficiency diagnosed before starting ketogenic diet

Background

Growth failure and growth hormone deficiency (GHD) have been reported as one accessory feature of GLUT1 deficiency syndrome (GLUT1DS), considered so far as a long-term adverse effects of ketogenic diet which is used to treat this condition.

Case presentation

We report the case of a 10-year-old Caucasian boy referred for short stature (height − 2.56 SDS) and delayed growth (growth velocity − 4.33 SDS) who was diagnosed with GHD and started treatment with recombinant human growth hormone (rhGH). Because of his history of seizures with infantile onset, deceleration of head growth with microcephaly, ataxia, and moderate intellectual disability, a lumbar puncture was performed, which revealed a low CSF glucose concentration with a very low CSF-to-blood glucose ratio (< 0.4), and genetic tests detected a SLC2A1 gene exon 1 deletion confirming a diagnosis of GLUT1DS. Ketogenic diet was started. After 5.5 years of rhGH treatment his height was normalized (− 1.15 SDS). No side effects were reported during treatment, particularly on glycemic metabolism.

Conclusions

This is the first case of GHD in a Caucasian boy with GLUT1DS diagnosed before starting ketogenic diet, with a good response to rhGH treatment and absence of side effects. We speculate that GHD may represent a poorly recognized clinical feature of GLUT1DS rather than a complication due to ketogenic diet. Under-diagnosis may derive from the fact that growth failure is usually ascribed to ketogenic diet and therefore not further investigated. Pediatric neurologists need to be alerted to the possible presence of GHD in patients with GLUT1DS with slow growth, while pediatric endocrinologist need to refer GHD patients with additional features (motor and cognitive developmental delay, seizures with infantile onset, deceleration of head growth with acquired microcephaly, movement disorder with ataxia, dystonia, and spasticity) that may suggest GLUT1DS.

Potential for diet to prevent and remediate cognitive deficits in neurological disorders

The pathophysiology of many neurological disorders involves oxidative stress, neuroinflammation, and mitochondrial dysfunction. There is now substantial evidence that diet can decrease these forms of pathophysiology, and an emerging body of literature relatedly suggests that diet can also prevent or even remediate the cognitive deficits observed in neurological disorders that exhibit such pathology (eg, Alzheimer's disease, multiple sclerosis, age-related cognitive decline, epilepsy). The current review summarizes the emerging evidence in relation to whole diets prominent in the scientific literature-ketogenic, caloric restriction, high polyphenol, and Mediterranean diets-and provides a discussion of the possible underlying neurophysiological mechanisms.

Quality of Life in Chronic Ketogenic Diet Treatment: The GLUT1DS Population Perspective

BACKGROUND

Glucose transporter type 1 deficiency syndrome (GLUT1DS) is a rare, genetically determined neurological disorder, for which Ketogenic Diet (KD) represents the gold standard life-long treatment. The aim of this study is to investigate health related quality of life in a well characterized cohort of patients affected by GLUT1DS treated with KD, evaluating factors that can influence patients' and parents' quality of life perception.

METHODS

This is a double center exploratory research study. A postal survey with auto-administrable questionnaires was conducted among 17 subjects (aged 3-22 years) with diagnosis of GLUT1DS, receiving a stable KD treatment for more than 1 year. The Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Scales was adopted. Clinical variables analyzed in relation to quality of life were frequency of epileptic seizures and movement disorder since KD introduction, presence of intellectual disability (ID), and KD ratio.

RESULTS

Quality of life global scores were impaired both in parents' and children's perspectives, with a significant concordance. Taking into consideration subscales, the average was 64.17 (range 10-100) for physical functioning, 74.23 (range 30-100) for emotional functioning, 62.64 (range 10-100) for social functioning, and 56 (range 15-92) for school functioning.

CONCLUSIONS

In patients with GLUT1DS the quality of life perception is comparable to that of other patients with chronic disease. In our sample, the presence of movement disorder seems to be a crucial element in quality of life perception.

What do parents expect from a genetic diagnosis of their child with intellectual disability?

BACKGROUND

Caring for a child with intellectual disability (ID) has been associated with increased social and psychological burdens. Diagnostic and prognostic uncertainty may enhance emotional stress in families.

METHOD

The present authors assessed the motivations, expectations, mental health, physical health and the quality of life of 194 parents whose children with intellectual disability were undergoing a genetic diagnostic workup.

RESULTS

Most parents considered a diagnosis highly relevant for their own emotional relief, their child's therapies and education, or family planning. Parental mental health was significantly lower compared with the normative sample, but physical health was not different. The severity of the child's intellectual disability correlated negatively with their parents' mental and physical health, quality of life, and positively with parental anxiety.

CONCLUSION

Healthcare providers should be aware of the disadvantages facing families with intellectually disabled children. Receiving practical, social and psychological support as well as genetic testing might be particularly relevant for families with severely disabled children.

Overall cognitive profiles in patients with GLUT1 Deficiency Syndrome

INTRODUCTION

Glucose Transporter Type I Deficiency Syndrome (GLUT1DS) classical symptoms are seizures, involuntary movements, and cognitive impairment but so far the literature has not devoted much attention to the last.

METHODS

In our retrospective study involving 25 patients with established GLUT1DS diagnosis, we describe the cognitive impairment of these patients in detail and their response to the ketogenic diet in terms of cognitive improvement.

RESULTS

We outlined a specific cognitive profile where performance skills were more affected than verbal ones, with prominent deficiencies in visuospatial and visuomotor abilities. We demonstrated the efficacy of ketogenic diet (KD) on cognitive outcome, with particular improvement tin total and verbal IQ; we found that timing of KD introduction was inversely related to IQ outcome: the later the starting of KD, the lower the IQ, more notable nonverbal scale (verbal IQ correlation coefficient -0.634, p-value = 0.015). We found a significant direct correlation between cognition and CSF/blood glucose ratio values: the higher the ratio, the better the cognitive improvement in response to diet (from T0-baseline evaluation to T1 on average 18 months after introduction of KD-: TIQ correlation coefficient 0.592, p-value = 0.26; VIQ correlation coefficient 0.555, p-value = 0.039). Finally, we demonstrated that a longer duration of treatment is necessary to find an improvement in patients with "severely low ratio."

CONCLUSION

Our results were consistent with the hypothesis that timing of the diet introduction is a predictive factor of cognitive outcome in these patients, confirming that earlier initiation of the diet may prevent the onset of all GLUT1DS symptoms: epilepsy, movement disorders, and cognitive impairment.

Cognitive benefits of the ketogenic diet in patients with epilepsy: A systematic overview

The ketogenic diet (KD) has been found to be effective in reducing seizures in patients with treatment-refractory epilepsy. Less attention has been paid to additional cognitive benefits of KD. The aim of the present paper was to provide a comprehensive overview of the studies reporting effects on cognition after KD treatment in adults and children with epilepsy. To address this aim, the clinical literature on cognitive effects of KD in patients with epilepsy was reviewed using a systematic approach. We conclude that using subjective assessments of the patient's experience, cognitive improvements are frequently reported during KD treatment in the domains of alertness, attention, and global cognition. Studies that used objective neuropsychological tests confirmed benefits on alertness but found no improvement in global cognition. There are indications that these improvements are caused by both seizure reduction and direct effects of KD on cognition. The improvements appear to be unrelated to medication reduction, age when KD is started, type of KD, and sleep improvement. The findings in the present overview contribute to a better understanding of the beneficial effects of KD in patients with epilepsy.

Experience with MAD on children with epilepsy in Egypt after classic KD failure

BACKGROUND AND AIM

Modified Atkins diet (MAD) is a less restrictive type of ketogenic diet (KD) as compared to the classic one. The aim of this study was to evaluate the impact of 9 months MAD treatment on the growth and seizure control in patients with intractable epilepsy as well as the quality of life (QoL) of their mothers.

SUBJECTS AND METHODS

The study included 15 patients with intractable epilepsy who could not tolerate their classic KD management plan. From the 15 recruited cases, only seven patients completed this nine months prospective study. After neurological reassessment, the patients were prescribed MAD tailored from the local Egyptian ingredients. Arabic translation of the WHO Quality of life Instruments (WHOQOL-BREF) scale was calculated for the mothers initially and 9 months later. Daily seizure frequency with severity assessment by Chalfont scale was recorded as well as monthly weight and length throughout the study period.

RESULTS

Mothers 'QoL in all WHOQOL-BREF domains significantly improved (P < .001) after nine months follow-up coupled by significant decrease in Chalfont scores from 51.00 ± 15.45 to 20.57 ± 21.45 and daily seizure frequency from 13.29 ± 6.99 to 2.71 ± 3.68. Regarding anthropometric data, there was significant increase in patients' weight and length as well as in the z-score for weight and length.

CONCLUSION

After nine months of MAD, growth and seizure parameters significantly improved in the intractable epilepsy patients as well as their mothers& QoL. We thus recommend MAD as a more flexible alternative in intractable epilepsy patients who can not tolerate classic KD.

Slowly progressive leukodystrophy in an adolescent male with phosphoglycerate kinase deficiency

We report the case of an 18-year-old man with a phosphoglycerate kinase (PGK) deficiency who had slowly progressive leukodystrophy during adolescence. The patient had a history of severe neonatal jaundice, hemolytic crisis with rhabdomyolysis triggered by febrile viral infections, dysarthria, and intellectual disability during early childhood. Clumsiness in walking and writing became obvious at ∼10years of age. Evaluations performed by us on the 18-year-old patient confirmed the presence of pyramidal tract signs, increased muscle tone, and generalized dystonia. Brain magnetic resonance (MR) imaging revealed leukodystrophy in the periventricular white matter, posterior limbs of the internal capsule, dorsal pons, and middle cerebellar peduncles. Compared to MR images acquired at 9years of age, MR images acquired at 18years of age showed that the white matter atrophy had progressed. The PGK deficiency was diagnosed by identifying a known missense mutation in PGK1 (c.1060G>C) through comprehensive target capture sequencing and by observing low PGK activity in his red blood cells. The patient underwent a ketogenic diet for 2weeks, which we expected would increase adenosine triphosphate levels through sources other than the PGK-associated glycolytic pathway. The diet was not tolerated owing to the unexpected emergence of hemolysis. Hemolytic anemia, neurological dysfunction, and myopathy are often associated with PGK deficiencies. However, leukodystrophy as a symptom of PGK deficiency has not been reported previously. Our case highlights the progressive nature of the neurological complications related to PGK deficiencies. Therefore, long-term follow-up is recommended, even if neurological impairments are not obvious during childhood.

How Can a Ketogenic Diet Improve Motor Function?

A ketogenic diet (KD) is a normocaloric diet composed by high fat (80-90%), low carbohydrate, and low protein consumption that induces fasting-like effects. KD increases ketone body (KBs) production and its concentration in the blood, providing the brain an alternative energy supply that enhances oxidative mitochondrial metabolism. In addition to its profound impact on neuro-metabolism and bioenergetics, the neuroprotective effect of specific polyunsaturated fatty acids and KBs involves pleiotropic mechanisms, such as the modulation of neuronal membrane excitability, inflammation, or reactive oxygen species production. KD is a therapy that has been used for almost a century to treat medically intractable epilepsy and has been increasingly explored in a number of neurological diseases. Motor function has also been shown to be improved by KD and/or medium-chain triglyceride diets in rodent models of Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and spinal cord injury. These studies have proposed that KD may induce a modification in synaptic morphology and function, involving ionic channels, glutamatergic transmission, or synaptic vesicular cycling machinery. However, little is understood about the molecular mechanisms underlying the impact of KD on motor function and the perspectives of its use to acquire the neuromuscular effects. The aim of this review is to explore the conditions through which KD might improve motor function. First, we will describe the main consequences of KD exposure in tissues involved in motor function. Second, we will report and discuss the relevance of KD in pre-clinical and clinical trials in the major diseases presenting motor dysfunction.

Precision therapy for epilepsy due to KCNT1 mutations

Objective

To evaluate quinidine as a precision therapy for severe epilepsy due to gain of function mutations in the potassium channel gene KCNT1.

Methods

A single-center, inpatient, order-randomized, blinded, placebo-controlled, crossover trial of oral quinidine included 6 patients with severe autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) due to KCNT1 mutation. Order was block randomized and blinded. Four-day treatment blocks were used with a 2-day washout between. Dose started at 900 mg over 3 divided doses then, in subsequent participants, was reduced to 600 mg, then 300 mg. Primary outcome was seizure frequency measured on continuous video-EEG in those completing the trial.

Results

Prolonged QT interval occurred in the first 2 patients at doses of 900 and 600 mg quinidine per day, respectively, despite serum quinidine levels well below the therapeutic range (0.61 and 0.51 μg/mL, reference range 1.3–5.0 μg/mL). Four patients completed treatment with 300 mg/d without adverse events. Patients completing the trial had very frequent seizures (mean 14 per day, SD 7, median 13, interquartile range 10–18). Seizures per day were nonsignificantly increased by quinidine (median 2, 95% confidence interval −1.5 to +5, p = 0.15) and no patient had a 50% seizure reduction.

Conclusion

Quinidine did not show efficacy in adults and teenagers with ADNFLE. Dose-limiting cardiac side effects were observed even in the presence of low measured serum quinidine levels. Although small, this trial suggests use of quinidine in ADNFLE is likely to be ineffective coupled with considerable cardiac risks.

Clinical trials registration

Australian Therapeutic Goods Administration Clinical Trial Registry (trial number 2015/0151).

Classification of evidence

This study provides Class II evidence that for persons with severe epilepsy due to gain of function mutations in the potassium channel gene KCNT1, quinidine does not significantly reduce seizure frequency.

[Research advances in hereditary epilepsy and precision drug therapy]

Epilepsy is a common nervous system disease. It has been found that the pathogenesis of epilepsy is associated mutations in various genes, including genes encoding voltage-dependent ion channel, genes encoding ligand-gated ion channel, and solute carrier family genes. Different types of epilepsy caused by different mutations have different responses to drugs, and therefore, diagnosis and medication guidance based on genes are new thoughts for developing therapies. With the application of next-generation sequencing technology, more and more genes will be determined, which helps to further study the pathogenic mechanism of mutant genes and provides a basis for precision drug therapy for epilepsy.

Elucidation of the complex metabolic profile of cerebrospinal fluid using an untargeted biochemical profiling assay

We sought to determine the molecular composition of human cerebrospinal fluid (CSF) and identify the biochemical pathways represented in CSF to understand the potential for untargeted screening of inborn errors of metabolism (IEMs). Biochemical profiles for each sample were obtained using an integrated metabolomics workflow comprised of four chromatographic techniques followed by mass spectrometry. Secondarily, we wanted to compare the biochemical profile of CSF with those of plasma and urine within the integrated mass spectrometric-based metabolomic workflow. Three sample types, CSF (N=30), urine (N=40) and EDTA plasma (N=31), were analyzed from retrospectively collected pediatric cohorts of equivalent age and gender characteristics. We identified 435 biochemicals in CSF representing numerous biological and chemical/structural families. Sixty-three percent (273 of 435) of the biochemicals detected in CSF also were detected in urine and plasma, another 32% (140 of 435) were detected in either plasma or urine, and 5% (22 of 435) were detected only in CSF. Analyses of several metabolites showed agreement between clinically useful assays and the metabolomics approach. An additional set of CSF and plasma samples collected from the same patient revealed correlation between several biochemicals detected in paired samples. Finally, analysis of CSF from a pediatric case with dihydropteridine reductase (DHPR) deficiency demonstrated the utility of untargeted global metabolic phenotyping as a broad assessment to screen samples from patients with undifferentiated phenotypes. The results indicate a single CSF sample processed with an integrated metabolomics workflow can be used to identify a large breadth of biochemicals that could be useful for identifying disrupted metabolic patterns associated with IEMs.

Pediatric Autoimmune Epileptic Encephalopathies

Pediatric autoimmune epileptic encephalopathies are predominantly characterized by the presence of autoantibodies to the surface of neuronal proteins, for example, N-methyl-d-aspartate (NMDA) receptor antibodies, but also include diseases with non-cell surface antibodies (eg, anti-Hu, glutamic-acid decarboxylase antibodies). In some cases with distinct clinical and para-clinical features, an autoimmune epileptic encephalopathy can be diagnosed without the presence of an antibody and will also respond favorably to immunotherapy. In this review, we summarize the common presentations of pediatric autoimmune epileptic encephalopathies, treatments, and outcomes, and report recent findings in the field of epilepsy, encephalopathy, and the immune system.

Use of modified Atkins diet in glucose transporter type 1 deficiency syndrome

AIM

Glucose transporter type 1 deficiency syndrome (GLUT1-DS) results from impaired glucose transport into the brain, and is treated with a ketogenic diet. A few reports have suggested effectiveness of treatment using the modified Atkins diet (MAD). We aimed to assess the efficacy of MAD as a treatment for GLUT1-DS.

METHOD

We evaluated the efficacy of MAD in 10 patients (four males, six females; mean age at diagnosis [SD] 6.2y [1.7], min-max: 4mo-12y) with GLUT1-DS.

RESULTS

MAD was started at diagnosis in eight patients, including two infants. The mean duration (SD) under MAD was 2.5 [0.6] years (range 6mo-6y). Seven patients with epilepsy started MAD at GLUT1-DS diagnosis, and all experienced improvements in their epilepsy: five out of seven were seizure-free at M1, and three out of six at M3 and M6. The initiation of MAD allowed symptoms to be controlled in the three patients with movement disorders but without seizures. Two patients switched from the ketogenic diet to MAD. This switch was not responsible for the recurrence of any symptoms, and led to improvements in both physical abilities and growth parameters.

INTERPRETATION

MAD, which is a less restrictive and more palatable diet than the ketogenic diet, seems to have comparable effectiveness. Moreover, a switch from the ketogenic diet to MAD appears to be beneficial for patients with GLUT1-DS.

Understanding the susceptibility of dopamine neurons to mitochondrial stressors in Parkinson's disease

Mitochondria are undoubtedly changed in Parkinson's disease (PD), and mitochondrial functions are disrupted in genetic and pharmacologic models of PD. However, many of these changes might not truly drive neurodegeneration. PD is defined by the particular susceptibility of nigrostriatal dopamine (DA) neurons, but little is understood about the mitochondria in these cells. Here, we critically review the evidence that mitochondrial stressors cause PD. We then consider how changes in the intrinsic function of mitochondria and in their mass, distribution, and dynamics might synergize with an increased need for mitochondria and produce PD, and the importance of understanding how mitochondria contribute to its pathogenesis.

Epileptic activity is a surrogate for an underlying etiology and stopping the activity has a limited impact on developmental outcome

The concept of epileptic encephalopathy is important in clinical practice, but its relevance to an individual must be assessed in the appropriate context. Except in rare situations, epileptic activity is a surrogate for an underlying etiology, and stopping the activity has a limited impact on developmental outcome. Labeling a group of epilepsies as "the epileptic encephalopathies," risks minimizing the impact of epileptic activity on cognition and behavior more widely in epilepsy. Similarly, describing the encephalopathy associated with many infantile onset epilepsies as "epileptic" may be misleading. Finally, concentrating on the epileptic activity alone and not considering the wider consequences of the underlying etiology on cognitive and behavioral development, may focus research efforts and the search for improved therapies on too narrow a target. Therefore, epileptic encephalopathies should not be considered as a specific group of epilepsies but, rather, the concept of epileptic encephalopathy should be applicable to all types of epilepsies and epilepsy syndromes, whenever it is relevant in the clinical course of a particular individual, at any age.

Ketogenic diets in patients with inherited metabolic disorders

Ketogenic diets (KDs) are diets that bring on a metabolic condition comparable to fasting, usually without catabolism. Since the mid-1990s such diets have been widely used in patients with seizures/epilepsies, mostly children. This review focuses on the use of KDs in patients with various inherited metabolic disorders (IMD). In glucose transporter type 1 deficiency syndrome (GLUT1-DS) and pyruvate dehydrogenase complex (PDHc) deficiency, KDs are deemed the therapy of choice and directly target the underlying metabolic disorder. Moreover, in other IMD, mainly of intermediary metabolism such as glycogen storage diseases and disorders of mitochondrial energy supply, KDs may ameliorate clinical symptoms and laboratory parameters. KDs have also been used successfully to treat symptoms such as seizures/epilepsy in IMD, e.g. in urea cycle disorders and non-ketotic hyperglycinemia. As a note of caution, catabolism may cause the condition of patients with IMD to deteriorate and should thus be avoided during KDs. For this reason, careful monitoring (clinical, laboratory and apparatus-supported) is warranted. In some IMDs specific macronutrient supply is critical. Therefore, in cases of PDHc deficiency the carbohydrate intake tolerated without lactate increase and in urea cycle disorders the protein tolerance should be determined. Considering this, it is particularly important in patients with IMD that the use of KDs be individualized and well documented.

Effects of a ketogenic diet on hippocampal plasticity in freely moving juvenile rats

Ketogenic diets are low-carbohydrate, sufficient protein, high-fat diets with anticonvulsant activity used primarily as a treatment for pediatric epilepsy. The anticonvulsant mechanism is thought to involve elevating inhibition and/or otherwise limiting excitability in the brain. Such a mechanism, however, might also significantly affect normal brain activity and limit synaptic plasticity, effects that would be important to consider in the developing brain. To assess ketogenic diet effects on synaptic transmission and plasticity, electrophysiological recordings were performed at the perforant path/dentate gyrus synapse in awake, freely-behaving juvenile male rats. Electrodes were implanted 1 week prior to recording. Animals were fed regular chow or a ketogenic diet ad libitum for 3 weeks before recording. Although the ketogenic diet did not significantly alter baseline excitability (assessed by input–output curves) or short-term plasticity (using the paired-pulse ratio), it did reduce the magnitude of long-term potentiation at all poststimulation timepoints out to the last time measured (48 h). The results suggest an effect of ketogenic diet-feeding on the induction magnitude but not the maintenance of long-term potentiation. The lack of effect of the diet on baseline transmission and the paired-pulse ratio suggests a mechanism that limits excitation preferentially in conditions of strong stimulation, consonant with clinical reports in which the ketogenic diet alleviates seizures without a major impact on normal brain activity. Limiting plasticity in a seizure-susceptible network may limit seizure-induced epileptogenesis which may subserve the ongoing benefit of the ketogenic diet in epilepsy.

Brain and behavioral perturbations in rats following Western diet access

Energy dense "Western" diets (WD) are known to cause obesity as well as learning and memory impairments, blood-brain barrier damage, and psychological disturbances. Impaired glucose (GLUT1) and monocarboxylate (MCT1) transport may play a role in diet-induced dementia development. In contrast, ketogenic diets (KD) have been shown to be neuroprotective. We assessed the effect of 10, 40 and 90 days WD, KD and Chow maintenance on spontaneous alternation (SA) and vicarious trial and error (VTE) behaviors in male rats, then analyzed blood glucose, insulin, and ketone levels; and hippocampal GLUT1 and MCT1 mRNA. Compared to Chow and KD, rats fed WD had increased 90 day insulin levels. SA was decreased in WD rats at 10, but not 40 or 90 days. VTE was perturbed in WD-fed rats, particularly at 10 and 90 days, indicating hippocampal deficits. WD rats had lower hippocampal GLUT1 and MCT1 expression compared to Chow and KD, and KD rats had increased 90 day MCT1 expression compared to Chow and WD. These data suggest that WD reduces glucose and monocarboxylate transport at the hippocampus, which may result in learning and memory deficits. Further, KD consumption may be useful for MCT1 transporter recovery, which may benefit cognition.