Telemedicine for Ketogenic Dietary Treatment in Refractory Epilepsy and Inherited Metabolic Disease: State of Play and Future Perspectives.

Ketogenic dietary therapies (KDT) are diets that induce a metabolic condition comparable to fasting. All types of KDT comprise a reduction in carbohydrates whilst dietary fat is increased up to 90% of daily energy expenditure. The amount of protein is normal or slightly increased. KDT are effective, well studied and established as non-pharmacological treatments for pediatric patients with refractory epilepsy and specific inherited metabolic diseases such as Glucose Transporter Type 1 Deficiency Syndrome. Patients and caregivers have to contribute actively to their day-to-day care especially in terms of (self-) calculation and (self-) provision of dietary treatment as well as (self-) measurement of blood glucose and ketones for therapy monitoring. In addition, patients often have to deal with ever-changing drug treatment plans and need to document occurring seizures on a regular basis. With this review, we aim to identify existing tools and features of telemedicine used in the KDT context and further aim to derive implications for further research and development.

Fumarase deficiency: a difficult diagnosis and a challenging treatment approach

Introduction: Fumarase deficiency is a rare autosomal metabolic disease that curse with hypotonia, hyperlacticaemia and seizures. Diagnosis based in laboratory test might be done carefully, as most of metabolic diseases present similar symptomatology: hypotony, convulsions, lactic and pyruvic acidemia. Method: The objective is to analyse the pharmacological and nutritional approach of a neonate who presented symptoms of metabolic congenital disorders.Results:The patient is a three-month girl with heterozygote mutation in fumarase gene, who presented clinical manifestations of the altered enzyme function. She presented hyperlacticaemia, organic aciduria and alterations of amino acid levels. First diagnosis suspected was pyruvate dehydrogenase deficiency, so nutritional treatment with ketogenic diet was initiated. After medical discharge, she was hospitalized in emergency basis with cardiac arrest and metabolic decompensation. Genetic test revealed a heterozygote mutation in fumarase. Clinical symptomatology could have worsened because of the difficult diagnosis. Conclusions: Nutritional and pharmacological treatment of fumarase deficiency is considered essential for the patient’s evolution, but further researchers must be carried out to profoundly understand the mechanism underlying metabolic inborn errors. Multidisciplinary teams would manage the disease from the point of view of diverse clinician experts so the correct diagnosis and treatment would be decided with precision(AU)

Introducción: El déficit de fumarasa es una enfermedad rara del metabolismo, autosómica, que cursa con hipotonía, hiperlactacidemia y convulsiones. El diagnóstico basado en pruebas de laboratorio debe realizarse con precaución ya que la mayoría de enfermedades relacionadas con el metabolismo presentan la misma sintomatología: hipotonía, convulsiones y acidemia láctica y pirúvica. Método: Analizar retrospectivamente el manejo farmacológico y nutricional de un neonato con síntomas relacionados con errores del metabolismo congénitos.Resultados:La paciente de 3 meses de vida presentaba una mutación heterocigota en el gen de la fumarasa y síntomas relacionados con la alteración de la función enzima. La paciente presentaba hiperlactacidemia, aciduria orgánica y alteraciones analíticas de los aminoácidos. El primer diagnóstico supuesto fue un déficit de piruvato deshidrogenasa, por lo que se inició tratamiento nutricional con dieta cetogénica. Tras el alta de la paciente, volvió a ingresar por urgencias sufriendo una parada cardíaca y descompensación metabólica. El test genético reveló la presencia de una mutación heterocigota en el gen de la fumarasa. La sintomatología clínica pudo haber empeorado debido al difícil diagnóstico. Conclusiones: El tratamiento farmacológico y nutricional del déficit de fumarasa es esencial para la buena evolución del paciente, pero es necesario que se realicen más estudios para entender con profundidad el mecanismo de los errores congénitos del metabolismo Los equipos multidisciplinares permiten manejar la enfermedad desde distintos puntos de vista clínicos para un diagnóstico correcto y poder decidir el tratamiento adecuado con precisión(AU)

Comparison of Untargeted Metabolomic Profiling vs Traditional Metabolic Screening to Identify Inborn Errors of Metabolism.

Importance: Recent advances in newborn screening (NBS) have improved the diagnosis of inborn errors of metabolism (IEMs); however, many potentially treatable IEMs are not included on NBS panels, nor are they covered in standard, first-line biochemical testing. Objective: To examine the utility of untargeted metabolomics as a primary screening tool for IEMs by comparing the diagnostic rate of clinical metabolomics with the recommended traditional metabolic screening approach. Design, Setting, and Participants: This cross-sectional study compares data from 4464 clinical samples received from 1483 unrelated families referred for trio testing of plasma amino acids, plasma acylcarnitine profiling, and urine organic acids (June 2014 to October 2018) and 2000 consecutive plasma samples from 1807 unrelated families (July 2014 to February 2019) received for clinical metabolomic screening at a College of American Pathologists and Clinical Laboratory Improvement Amendments-certified biochemical genetics laboratory. Data analysis was performed from September 2019 to August 2020. Exposures: Metabolic and molecular tests performed at a genetic testing reference laboratory in the US and available clinical information for each patient were assessed to determine diagnostic rate. Main Outcomes and Measures: The diagnostic rate of traditional metabolic screening compared with clinical metabolomic profiling was assessed in the context of expanded NBS. Results: Of 1483 cases screened by the traditional approach, 912 patients (61.5%) were male and 1465 (98.8%) were pediatric (mean [SD] age, 4.1 [6.0] years; range, 0-65 years). A total of 19 families were identified with IEMs, resulting in a 1.3% diagnostic rate. A total of 14 IEMs were detected, including 3 conditions not included in the Recommended Uniform Screening Panel for NBS. Of the 1807 unrelated families undergoing plasma metabolomic profiling, 1059 patients (58.6%) were male, and 1665 (92.1%) were pediatric (mean [SD] age, 8.1 [10.4] years; range, 0-80 years). Screening identified 128 unique cases with IEMs, giving an overall diagnostic rate of 7.1%. In total, 70 different metabolic conditions were identified, including 49 conditions not presently included on the Recommended Uniform Screening Panel for NBS. Conclusions and Relevance: These findings suggest that untargeted metabolomics provided a 6-fold higher diagnostic yield compared with the conventional screening approach and identified a broader spectrum of IEMs. Notably, with the expansion of NBS programs, traditional metabolic testing approaches identify few disorders beyond those covered on the NBS. These data support the capability of clinical untargeted metabolomics in screening for IEMs and suggest that broader screening approaches should be considered in the initial evaluation for metabolic disorders.

Evaluation of Body Composition, Physical Activity, and Food Intake in Patients with Inborn Errors of Intermediary Metabolism.

Children with inborn errors of intermediary metabolism (IEiM) must follow special diets that restrict their intake of essential nutrients and may compromise normal growth and development. We evaluated body composition, bone mineral density, physical activity, and food intake in IEiM patients undergoing dietary treatment. IEiM patients (n = 99) aged 5-19 years and healthy age- and sex-matched controls (n = 98) were recruited and underwent dual-energy X-ray absorptiometry to evaluate anthropometric characteristics and body composition. Data on food intake and physical activity were also collected using validated questionnaires. The height z-score was significantly lower in IEiM patients than controls (-0.28 vs. 0.15; p = 0.008), particularly in those with carbohydrate and amino acid metabolism disorders. Significant differences in adiposity were observed between patients and controls for the waist circumference z-score (-0.08 vs. -0.58; p = 0.005), but not the body mass index z-score (0.56 vs. 0.42; p = 0.279). IEiM patients had a significantly lower total bone mineral density (BMD) than controls (0.89 vs. 1.6; p = 0.001) and a higher risk of osteopenia (z-score < -2, 33.3% vs. 20.4%) and osteoporosis (z-score < -2.5, 7.1% vs. 0%), but none presented fractures. There was a significant positive correlation between natural protein intake and BMD. Our results indicate that patients with IEiM undergoing dietary treatment, especially those with amino acid and carbohydrate metabolism disorders, present alterations in body composition, including a reduced height, a tendency towards overweight and obesity, and a reduced BMD.

Health-related quality of life in paediatric patients with intoxication-type inborn errors of metabolism: Analysis of an international data set.

Acute intoxication-type inborn errors of metabolism (IT-IEM) such as urea cycle disorders and non-acute IT-IEM such as phenylketonuria have a major impact on paediatric patients' life. Patients have to adhere to a strict diet but may face neurocognitive impairment and - in acute diseases - metabolic decompensations nevertheless. Research on the subjective burden of IT-IEM remains sparse. Studies with appropriate sample sizes are needed to make valid statements about health-related quality of life (HrQoL) in children and adolescents with IT-IEM. Six international metabolic centres contributed self-reports and proxy reports of HrQoL (assessed with the Paediatric Quality of Life Inventory) to the final data set (n = 251 patients; age range 2.3-18.8 years). To compare HrQoL of the patient sample with norm data and between acute and non-acute IT-IEM, t tests were conducted. To examine the influence of child age, sex, diagnosis and current dietary treatment on HrQoL, multiple linear regression analyses were conducted. Self-reports and proxy reporst showed significantly lower HrQoL total scores for children with IT-IEM compared to healthy children. Current dietary treatment significantly predicted lower proxy reported total HrQoL. Children with non-acute IT-IEM reported significantly lower psychosocial health and emotional functioning than children with acute IT-IEM. The patient sample showed significantly impaired HrQoL and a diet regimen remains a risk factor for lower HrQoL. Differences in HrQoL between acute and non-acute IT-IEM subgroups indicate that factors beyond symptom severity determine the perception of disease burden. Identifying these factors is of crucial importance to develop and implement appropriate interventions for those in need.

Effects of fasting, feeding and exercise on plasma acylcarnitines among subjects with CPT2D, VLCADD and LCHADD/TFPD.

BACKGROUND: The plasma acylcarnitine profile is frequently used as a biochemical assessment for follow-up in diagnosed patients with fatty acid oxidation disorders (FAODs). Disease specific acylcarnitine species are elevated during metabolic decompensation but there is clinical and biochemical heterogeneity among patients and limited data on the utility of an acylcarnitine profile for routine clinical monitoring. METHODS: We evaluated plasma acylcarnitine profiles from 30 diagnosed patients with long-chain FAODs (carnitine palmitoyltransferase-2 (CPT2), very long-chain acyl-CoA dehydrogenase (VLCAD), and long-chain 3-hydroxy acyl-CoA dehydrogenase or mitochondrial trifunctional protein (LCHAD/TFP) deficiencies) collected after an overnight fast, after feeding a controlled low-fat diet, and before and after moderate exercise. Our purpose was to describe the variability in this biomarker and how various physiologic states effect the acylcarnitine concentrations in circulation. RESULTS: Disease specific acylcarnitine species were higher after an overnight fast and decreased by approximately 60% two hours after a controlled breakfast meal. Moderate-intensity exercise increased the acylcarnitine species but it varied by diagnosis. When analyzed for a genotype/phenotype correlation, the presence of the common LCHADD mutation (c.1528G > C) was associated with higher levels of 3-hydroxyacylcarnitines than in patients with other mutations. CONCLUSIONS: We found that feeding consistently suppressed and that moderate intensity exercise increased disease specific acylcarnitine species, but the response to exercise was highly variable across subjects and diagnoses. The clinical utility of routine plasma acylcarnitine analysis for outpatient treatment monitoring remains questionable; however, if acylcarnitine profiles are measured in the clinical setting, standardized procedures are required for sample collection to be of value.

Health Status of French Young Patients with Inborn Errors of Metabolism with Lifelong Restricted Diet.

OBJECTIVE: To describe the health status of young patients affected by inborn errors of metabolism that require adherence to a restricted diet (IEMRDs) and to describe and compare their self- and proxy (parent)-reported quality of life (QoL) with reference values. STUDY DESIGN: A cross-sectional study was conducted in 2015-2017 in patients affected by IEMRDs (except phenylketonuria) younger than 18 years. Data collection was based on medical records, clinical examinations, parents' and children's interviews, and self-reported questionnaires. Measurements included clinical and healthcare data, child and family environment data, and self- and proxy (parent)-reported QoL. RESULTS: Of the 633 eligible participants, 578 were recruited (50.3% boys; mean age: 8.7 years); their anthropometric status did not differ from the general population. Approximately one-half of them had at least 1 complication of the disease. Their self-reported global QoL did not differ from that of the general population. However, relations with friends and leisure activities QoL domains were negatively impacted, whereas relations with medical staff, relations with parents, and self-esteem QoL domains were positively impacted. Their proxy (parent)-reported QoL was negatively impacted. CONCLUSIONS: Young patients affected by IEMRDs present a high rate of clinical complications. Although their proxy (parent)-reported QoL was negatively impacted, their self-reported QoL was variably impacted (both positively and negatively). These results may inform counseling for those who care for affected patients and their families.

Medical Foods for Inborn Errors of Metabolism: History, Current Status, and Critical Need.

Successful intervention for inborn errors of metabolism (IEMs) is a triumph of modern medicine. For many of these conditions, medical foods are the cornerstone of therapy and the only effective interventions preventing disability or death. Medical foods are designed for patients with limited or impaired capacity to ingest, digest, absorb, or metabolize ordinary foods or nutrients, whereby dietary management cannot be achieved by modification of the normal diet alone. In the United States today, access to medical foods is not ensured for many individuals who are affected despite their proven efficacy in the treatment of IEMs, their universal use as the mainstay of IEM management, the endorsement of their use by professional medical organizations, and the obvious desire of families for effective care. Medical foods are not sufficiently covered by many health insurance plans in the United States and, without insurance coverage, many families cannot afford their high cost. In this review, we outline the history of medical foods, define their medical necessity, discuss the barriers to access and reimbursement resulting from the regulatory status of medical foods, and summarize previous efforts to improve access. The Advisory Committee on Heritable Disorders in Newborns and Children asserts that it is time to provide stable and affordable access to the effective management required for optimal outcomes through the life span of patients affected with IEMs. Medical foods as defined by the US Food and Drug Administration should be covered as required medical benefits for persons of all ages diagnosed with an IEM.

Vitamin D Levels and Bone Mineral Density in Inborn Errors of Metabolism Requiring Specialised Diets.

OBJECTIVE: To evaluate vitamin D levels and bone mineral density in patients with dietary limitations due to inborn errors of metabolism (IEM) and its correlation with diets. STUDY DESIGN: Retrospective study. PLACE AND DURATION OF STUDY: Department of Pediatrics, Division of Pediatric Metabolism and Nutrition, Gazi University Hospital, Turkey, from March to Semtember 2016. METHODOLOGY: The study is a retrospective review of 115 patients. Information about vitamin D status, bone mineral density (BMD) measurement and anthropometric parametres were collected. Patients were divided into two major groups, receiving protein-restricted diets (n=83) and lactose-restricted diets (n=32). Data of 110 healthy children were used as the control group. RESULTS: Mean vitamin D level of patients with special diets 28.1 ±14.9 ng/ml while mean level of healthy controls was 26.6 ±12.27 ng/ml. Levels of 26.8% (n=26/97) patients were found to be deficient and 34% (n=33/97) were found to be insufficient. No statistically significant differences were found between vitamin D levels and BMD of patients and healthy controls. BMD was not influenced by vitamin D levels. CONCLUSION: Low BMD may be encountered in IEM, independent of vitamin D levels and revision of diet for adequacy of essential nutrients; and follow-up for dietary compliance is inevitable.

Nutrition process improvements for adult inpatients with inborn errors of metabolism using the i-PARIHS framework.

AIM: This project aimed to implement consensus recommendations and innovations that improve dietetic services to promote timely referral to optimise nutritional management for adult inpatients with inborn errors of metabolism (IEM). METHODS: The i-PARIHS framework was used to identify service gaps, implement innovations and evaluate the innovations within this single-site study. The constructs of this framework are: (i) review of the evidence; (ii) recognising patients and staff knowledge and attitudes; (iii) acknowledging the local context; and (iv) the facilitators role. This included a literature review and metabolic centre service comparisons to investigate dietetic referral and foodservice processes to inform the innovation. A 12-month chart audit (6 months retrospective and prospective of implemented innovation, respectively) to evaluate newly established dietetic referral and IEM nutrition provision procedures was also completed. RESULTS: The innovations implemented encompassed a clinical alert triggering urgent referral, nutrition sick day plans and metabolic diet and formula prescription via an 'alert' tab in electronic records. Eleven metabolic protein-restricted diets and nine formula recipes were introduced. Prior to the innovations, only 53% (n = 19/36) of inpatients with IEM were assessed by the dietitian and received appropriate nutrition within 24 hours. Following implementation of the innovations, 100% (n = 11/11) of inpatients with IEM received timely dietetic assessment and therapeutic nutrition. CONCLUSIONS: Implementation of innovations developed using the i-PARIHS framework is effective in timely notification of the metabolic dietitian of referrals. This ensures optimal nutritional management during admissions which is required in this group of high-risk patients.

Effects of fasting on warfarin sensitivity index in patients undergoing cardiovascular surgery.

PURPOSE: Warfarin shows large inter- and intra-individual variabilities in its pharmacokinetics and pharmacodynamics. Sufficient understanding of factors affecting the response to warfarin is necessary to achieve improved outcomes for warfarin therapy. In this study, we evaluated effects of fasting on the anticoagulant properties of warfarin. METHODS: We conducted a retrospective observational study involving a total of 58 patients, who received cardiovascular surgeries and subsequent warfarin therapy. The effect of dietary intake on the anticoagulant properties with warfarin was assessed by measurement of the international normalized ratio of prothrombin time (PT-INR): the anticoagulant activities of warfarin were expressed as the warfarin sensitivity index (WSI). Additionally, fluctuations in WSI during the study period were obtained as differences between the maximum and minimum WSI. RESULTS: The maximum PT-INR and WSI values were significantly higher for patients who were fasting for different reasons during the postoperative period than those in the group without reduced dietary intake. The differences between maximum and minimum WSI in the fasting group significantly increased compared with those in the groups with moderate or no reduced dietary intake. Meanwhile, effects of other markers of clinical conditions including the baseline Child-Pugh score and Charlson Comorbidity Index on WSI were not significant. CONCLUSIONS: Our results indicate that postoperative fasting was significantly associated with the anticoagulation activity of warfarin. In patients fasting for different reasons during the postoperative period, closer control of PT-INR values and warfarin adjustments may be required to avoid adverse effects such as bleeding in warfarin treatment.

Current strategies for the treatment of inborn errors of metabolism.

Inborn errors of metabolism (IEMs) are a large group of inherited disorders characterized by disruption of metabolic pathways due to deficient enzymes, cofactors, or transporters. The rapid advances in the understanding of the molecular pathophysiology of many IEMs, have led to significant progress in the development of many new treatments. The institution and continued expansion of newborn screening provide the opportunity for early treatment, leading to reduced morbidity and mortality. This review provides an overview of the diverse therapeutic approaches and recent advances in the treatment of IEMs that focus on the basic principles of reducing substrate accumulation, replacing or enhancing absent or reduced enzyme or cofactor, and supplementing product deficiency. In addition, the challenges and obstacles of current treatment modalities and future treatment perspectives are reviewed and discussed.

3-hydroxy-3-methylglutaryl-CoA lyase deficiency: a case report and literature review / Deficiencia de la 3-hidroxi-3-metilglutaril-CoA liasa: un caso clínico y revisión de la literatura

Introduction: 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase deficiency is an autosomal recessive disorder that usually presents in the neonatal period with vomiting, metabolic acidosis, hypoglycemia and absent ketonuria. Few cases are reported in the literature, and optimal dietary management and long term outcome are not fully understood. Case report: We report a 2 year old girl with HMG-CoA-lyase deficiency who had limited fasting tolerance on a low protein diet, with several recurrent hospital admissions with severe hypoketotic hypoglycaemia and metabolic acidosis. We also review the dietary management and outcome of other reported cases in the literature. Discussion: In order to define optimal dietary treatment, it is important to collect higher numbers of case studies with detailed dietary management, fasting times and outcome (AU)

Introducción: la deficiencia de la 3-hidroxi-3-metilglutaril-CoA (HMG-CoA) liasa es un desorden autosómico recesivo que normalmente se presenta en la infancia con vómitos, acidosis metabólica, hipoglicemia y sin cetonuria. Se han publicado pocos casos en la literatura científica sobre el mejor tratamiento dietético para el adecuado desarrollo de los pacientes a largo plazo, por lo que esta deficiencia no es bien conocida. Caso clínico: presentamos una niña de 2 años con deficiencia de la 3-hidroxi-3-metilglutaril-CoA (HMG-CoA) liasa. Recibiendo una dieta baja en proteína con una tolerancia de ayuno limitada con episodios recurrentes de admisión hospitalaria con hipoglicemia hipoketotica y acidosis metabólica. También hemos revisado el tratamiento dietético y el desarrollo de otros casos publicados en la literatura científica. Discusión: es importante recoger más casos clínicos describiendo el tratamiento dietético seguido, el tiempo máximo de ayuno y el desarrollo de los pacientes con el objetivo de definir el mejor tratamiento (AU)

Dietary patterns, cost and compliance with low-protein diet of phenylketonuria and other inherited metabolic diseases.

BACKGROUND/OBJECTIVES: Phenylketonuria (PKU) and several other inherited metabolic diseases (IMD) require a lifelong low-protein diet (LPD), otherwise they lead to many health complications. LPDs, however, carry a significant economic burden for patients and their families. The objective of this study was to explore the costs of low-protein foods (LPFs) necessary for LPD as well as dietary patterns and compliance towards an LPD. SUBJECTS/METHODS: A detailed questionnaire was created in cooperation with National Association of PKU and other IMD (NSPKU), and consequently sent to all NSPKU members treated with an LPD (n=303). A total of 184 respondents from the Czech Republic were included in the study (174 had PKU, 10 had other IMD). RESULTS: The average daily consumption of LPF was equal to 411.7 g (PKU) and 345.6 g (other IMD), which corresponds to energy value of 5558 kJ and 4438 kJ, respectively, per patient per day. Patients mostly consumed low-protein flour (≈30% of energy intake), pasta (≈18%), basic pastry (≈15%) and sweets (≈10%). The average monthly costs of LPDs were equal to [euro ]130 (PKU) and [euro ]129 (other IMD) per patient per month. The compliance with LPD was decreasing with increasing age (P<0.0001). CONCLUSIONS: This is the largest study examining costs and dietary patterns of LPDs in patients with PKU and the first study of this kind in other IMD patients requiring an LPD. The study clearly showed that an LPD carries a very high economic burden for families, which may lead to less LPD compliance and potential severe health consequences.

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.