Long-chain Fatty Acid Oxidation Disorders Research Articles

Triheptanoin in patients with long-chain fatty acid oxidation disorders: clinical experience in Italy

BackgroundLong-chain fatty acid oxidation disorders (LC-FAOD) are rare and potentially life-threatening diseases that cause deficient energy production and accumulation of toxic metabolites. Despite dietary management, adherence to maximum fasting guidelines, restricted long-chain triglyceride intake and supplementation with medium-chain triglyceride (MCT) oil (current standard of care), most patients experience recurrent decompensation episodes that can require hospitalisation. Herein, we analysed the effectiveness and safety of triheptanoin (a highly purified, synthetic medium odd-chain triglyceride) treatment in a cohort of Italian patients with LC-FAOD.MethodsThis retrospective, nationwide study included nine patients with LC-FAOD who switched from standard therapy with MCT oil to triheptanoin oral liquid. Data were collected between 2018 and 2022. Clinical outcome measures were the number and duration of intercurrent catabolic episodes and number and duration of metabolic decompensation episodes requiring hospitalisation. Creatine kinase (CK) levels and treatment-related adverse effects were also reported.ResultsPatients were provided a mean ± standard deviation (SD) triheptanoin dose of 1.5 ± 0.9 g/kg/day in four divided administrations, which accounted for 23.9 ± 8.9% of patients’ total daily caloric intake. Triheptanoin treatment was started between 2.7 and 16 years of age and was continued for 2.2 ± 0.9 years. The number of intercurrent catabolic episodes during triheptanoin treatment was significantly lower than during MCT therapy (4.3 ± 5.3 vs 22.0 ± 22.2; p = 0.034), as were the number of metabolic decompensations requiring hospitalisation (mean ± SD: 2.0 ± 2.5 vs 18.3 ± 17.7; p = 0.014), and annualised hospitalisation rates and duration. Mean CK levels (outside metabolic decompensation episodes) were lower with triheptanoin treatment versus MCT oil for seven patients. No intensive care unit admissions were required during triheptanoin treatment. Epigastric pain and diarrhoea were recorded as adverse effects during both MCT and triheptanoin treatment.ConclusionsThe significant improvement in clinical outcome measures after the administration of triheptanoin highlights that this treatment approach can be more effective than MCT supplementation in patients with LC-FAOD. Triheptanoin was well tolerated and decreased the number of intercurrent catabolic episodes, metabolic decompensation episodes requiring hospitalisation, and the annualised rate and duration of hospitalisations.

Clinical manifestations, healthcare resource utilization, and costs among patients with long-chain fatty acid oxidation disorders: a retrospective claims database analysis

Objective Long-chain fatty acid oxidation disorders (LC-FAOD) are a group of rare genetic inborn errors of metabolism. Clinical manifestations may result in frequent healthcare visits, hospitalizations, and early death. This retrospective cohort study assessed manifestations, healthcare resource use (HRU), direct medical costs, and the impact of COVID-19 on HRU among patients with LC-FAOD. Methods The IQVIA PharMetrics Plus database was searched for pediatric (0–17 years) and adult (≥18 years) patients with confirmed LC-FAOD (ICD-10-CM Diagnosis Code E71.310) and ≥12 months continuous enrollment (CE) between January 2016-February 2020. A non–LC-FAOD general population cohort was randomly selected and matched using 1:20 exact matching on age, gender, payer type, and CE start year. Manifestations were identified via ICD-10 diagnosis codes (any billing position). Overall HRU and attributable costs were stratified by care setting. Pre-COVID-19 (March 2019–February 2020) and during COVID-19 (March 2020-February 2021) HRU was assessed among a subgroup of patients and the general population. Outcomes were evaluated among children and adults, respectively. Results 423 patients with LC-FAOD (47% female; 79.7% children) were included. The mean enrollment duration was 2.6 ± 1.2 years. 22.6% of children with LC-FAOD had at least one major clinical event (MCE), consisting of rhabdomyolysis (10.1%), hypoglycemia (9.8%), or cardiomyopathy (8.6%) versus 1.5% overall occurrence in the general population. Adults with LC-FAOD had a higher incidence of MCEs (37.2%) than children with LC-FAOD. Annualized all-cause HRU in all care settings and mean total annualized medical costs (children: $17,082 vs $4144; adults: $43,602 vs $3949) were higher in patients with LC-FAOD versus the general population. Patients with LC-FAOD had substantially fewer healthcare visits during COVID-19 across care settings than during the pre-COVID-19 period. Conclusions LC-FAOD impart a high burden on patients. Extended hospital stays and increased outpatient management were especially pronounced for adults and for patients with ≥1 MCE, resulting in substantially higher medical costs than the general population.

Monocyte and macrophage profiles in patients with inherited long-chain fatty acid oxidation disorders

Patients with inherited disorders of the long-chain fatty acid oxidation (lcFAO) machinery present with a heterogeneous profile of disease manifestations and aggravation of symptoms is often triggered by inflammatory activation. Monocytes and macrophages are innate immune cells that play a major role in the onset and resolution of inflammation. These cells undergo metabolic rewiring upon activation including the regulation of the FAO rate. The rewiring of FAO and the effect of lcFAO disorders (lcFAOD) on human monocyte and macrophage phenotype and function remain largely unknown. Here, we performed extensive phenotyping of circulating monocytes and analyzed plasma cytokine levels in 11 lcFAOD patients and 11 matched control subjects. In patients with lcFAOD, we observed induced plasma levels of the inflammatory cytokines IL-1β and IL-6, and enhanced CD206 and CD62L surface marker expression in circulating monocyte subsets. To mimic the most common lcFAOD very-long-chain acyl-CoA dehydrogenase disorder (VLCADD), we used siRNA-mediated knockdown of the ACADVL gene (encoding VLCAD) in macrophages derived from healthy volunteers. Hereby, we found that siVLCAD affected IL-4-induced alternative macrophage activation while leaving LPS responses and cellular metabolism intact. In the same line, monocyte-derived macrophages from lcFAOD patients had elevated levels of the IL-4-induced alternative macrophage markers CD206 and CD200R. Still, they did not show major metabolic defects or changes in the LPS-induced inflammatory response. Our results indicate that monocytes and macrophages from lcFAOD patients present no major inflammatory or metabolic differences and show that IL-4-induced surface markers are intertwined with lcFAO in human macrophages.

Human inborn errors of long-chain fatty acid oxidation show impaired inflammatory responses to TLR4-ligand LPS.

Stimulation of mammalian cells with inflammatory inducers such as lipopolysaccharide (LPS) leads to alterations in activity of central cellular metabolic pathways. Interestingly, these metabolic changes seem to be important for subsequent release of pro-inflammatory cytokines. This has become particularly clear for enzymes of tricarboxylic acid (TCA) cycle such as succinate dehydrogenase (SDH). LPS leads to inhibition of SDH activity and accumulation of succinate to enhance the LPS-induced formation of IL-1β. If enzymes involved in beta-oxidation of fatty acids are important for sufficient responses to LPS is currently not clear. Using cells from various patients with inborn long-chain fatty acid oxidation disorders (lcFAOD), we report that disease-causing deleterious variants of Electron Transfer Flavoprotein Dehydrogenase (ETFDH) and of Very Long Chain Acyl-CoA Dehydrogenase (ACADVL), both cause insufficient inflammatory responses to stimulation with LPS. The insufficiencies included reduced TLR4 expression levels, impaired TLR4 signaling, and reduced or absent induction of pro-inflammatory cytokines such as IL-6. The insufficient responses to LPS were reproduced in cells from healthy controls by targeted loss-of-function of either ETFDH or ACADVL, supporting that the deleterious ETFDH and ACADVL variants cause the attenuated responses to LPS. ETFDH and ACADVL encode two distinct enzymes both involved in fatty acid beta-oxidation, and patients with these deficiencies cannot sufficiently metabolize long-chain fatty acids. We report that genes important for beta-oxidation of long-chain fatty acids are also important for inflammatory responses to an acute immunogen trigger like LPS, which may have important implications for understanding infection and other metabolic stress induced disease pathology in lcFAODs.

What is the impact of long-chain fatty acid oxidation disorders on everyday life? Plain language summary of a survey

What is this summary about? Long-chain fatty acid oxidation disorders (LC-FAOD for short) are a group of rare conditions where the body cannot use stored fat for energy. This leads to symptoms and health problems that can be life-threatening, but the impact of LC-FAOD on the everyday life of people with LC-FAOD and their caregivers has not been well studied. What was done? We conducted a burden of illness survey in the United States of people with LC-FAOD and their caregivers to help show the impact of this condition on their everyday life. The survey had 44 people who completed the survey (respondents): 14 adults (≥18 years) living with LC-FAOD and 30 caregivers reporting on 37 people with LC-FAOD. People with LC-FAOD reported on in the survey were 8 months to 67 years old (the average age was 16 years). What were the results? We found that the LC-FAOD symptoms impact people differently through the stages of life. People with LC-FAOD and their caregivers reported an impact on school and work, including missing work; the main reasons were hospitalizations (staying in the hospital as an inpatient) and physical symptoms. In addition, many people had trouble performing everyday activities, such as standing for 2 hours, walking a quarter of a mile, moving heavy objects, and doing household chores. Using a standard questionnaire, we found that the overall quality of life of people with LC-FAOD was lower than for the average American who does not have LC-FAOD. What do the results mean? The findings from the survey help show how LC-FAOD can impact the everyday life of people living with LC-FAOD and their caregivers. The findings provide people with LC-FAOD a better understanding of their condition and what they might expect. The findings also help researchers and healthcare providers support people with an LC-FAOD and their caregivers.

Early results from a long-term disease monitoring program in patients with long-chain fatty acid oxidation disorders

Early results from a long-term disease monitoring program in patients with long-chain fatty acid oxidation disorders

Revealing the genetic complexity of long-chain fatty acid oxidation disorders: Insights from a dynamic locus-specific gene database

Revealing the genetic complexity of long-chain fatty acid oxidation disorders: Insights from a dynamic locus-specific gene database

Long-chain Fatty Acid Oxidation Disorders, Early Diagnosis and Role of Breastfeeding

ZusammenfassungEin männliches Neugeborenes, zweites Kind nichtkonsanguiner Eltern, wurde termingerecht per Kaiserschnitt mit 38 + 6 Schwangerschaftswochen und einem Geburtsgewicht von 3340 g geboren. Bereits am 4. Lebenstag zeigten sich auffallende Symptome, darunter rezidivierendes Erbrechen, Hypoglykämie-Episoden und eine Gewichtsabnahme von über 10 %. Das Kind wurde zur weiteren Abklärung an ein medizinisches Zentrum mit Neugeborenen-Intensivstation transferiert. Das Neugeborenen-Screening (NGS) traf am 5. Lebenstag ein und wies auf eine langkettige Fettsäureoxidationsstörung hin (LC-FAOD). Eine umfassende Stoffwechselabklärung und genetische Diagnostik wurden eingeleitet, welches die Diagnose LCHAD-Defizienz im Verlauf bestätigte. Während des stationären Aufenthalts wurde der Fokus auf regelmäßige Stillmahlzeiten gelegt, um katabolen Phasen vorzubeugen. Der Säugling wurde am 12. Lebenstag auf die Normalstation verlegt und am 14. Lebenstag entlassen. Die multidisziplinäre Betreuung, regelmäßige ärztliche Überwachung und eine angepasste Ernährung spielten eine entscheidende Rolle im erfolgreichen Management der seltenen angeborenen Stoffwechselstörung. Das NGS hat eine wesentliche Bedeutung bei der frühzeitigen Erkennung gut beherrschbarer angeborener Stoffwechselstörungen. LC-FAODs beeinträchtigen den Abbau von Fettsäuren und können zu schweren gesundheitlichen Problemen führen. Die Symptome variieren, erfordern jedoch eine enge Zusammenarbeit verschiedener medizinischer Fachkräfte. Stillen bei Neugeborenen gilt als adäquate, altersentsprechende Ernährung, da es – auch für Kinder mit metabolischen Erkrankungen – zahlreiche gesundheitliche Vorteile für Kind und Mutter bietet und auch die Bindung zwischen Mutter und Kind fördert. Die einzigartige Zusammensetzung der Muttermilch passt sich den Bedürfnissen des Kindes an. Der geschilderte Fall betont die Bedeutung des NGS, die Zusammenarbeit verschiedener Fachbereiche sowie die Rolle von Stillen, Triheptanoin-Supplementierung im Verlauf und angepasster Ernährung im Umgang mit langkettigen Fettsäureoxidationsstörungen. Frühe Diagnose und ein umfassender Ansatz sind entscheidend für die bestmögliche Betreuung und Lebensqualität.

Major clinical events and healthcare resource use among patients with long-chain fatty acid oxidation disorders in the United States: Results from LC-FAOD Odyssey program

Major clinical events (MCEs) related to long-chain fatty acid oxidation disorders (LC-FAOD) in triheptanoin clinical trials include inpatient or emergency room (ER) visits for three major clinical manifestations: rhabdomyolysis, hypoglycemia, and cardiomyopathy. However, outcomes data outside of LC-FAOD clinical trials are limited. The non-interventional cohort LC-FAOD Odyssey study examines data derived from US medical records and patient reported outcomes to quantify LC-FAOD burden according to management strategy including MCE frequency and healthcare resource utilization (HRU).Thirty-four patients were analyzed of which 21 and 29 patients had received triheptanoin and/or medium chain triglycerides (MCT), respectively. 36% experienced MCEs while receiving triheptanoin versus 54% on MCT. Total mean annualized MCE rates on triheptanoin and MCT were 0.1 and 0.7, respectively. Annualized disease-related inpatient and ER events were lower on triheptanoin (0.2, 0.3, respectively) than MCT (1.2, 1.0, respectively). Patients were managed more in an outpatient setting on triheptanoin (8.9 annualized outpatient visits) vs MCT (7.9). Overall, this shows that those with LC-FAOD in the Odyssey program experienced fewer MCEs and less HRU in inpatient and ER settings during triheptanoin-treated periods compared with the MCT-treated periods. The MCE rate was lower after initiation of triheptanoin, consistent with clinical trials.

Using the C14:1/Medium-Chain Acylcarnitine Ratio Instead of C14:1 to Reduce False-Positive Results for Very-Long-Chain Acyl-CoA Dehydrogenase Deficiency in Newborn Screening in Japan.

Very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is a long-chain fatty acid oxidation disorder that manifests as either a severe phenotype associated with cardiomyopathy, a hypoglycemic phenotype, or a myopathic phenotype. As the hypoglycemic phenotype can cause sudden infant death, VLCAD deficiency is included in newborn screening (NBS) panels in many countries. The tetradecenoylcarnitine (C14:1) level in dried blood specimens is commonly used as a primary marker for VLCAD deficiency in NBS panels. Its ratio to acetylcarnitine (C2) and various other acylcarnitines is used as secondary markers. In Japan, tandem mass spectrometry-based NBS, initially launched as a pilot study in 1997, was introduced to the nationwide NBS program in 2013. In the present study, we evaluated levels of acylcarnitine with various chain lengths (C18 to C2), free carnitine, and their ratios in 175 infants who tested positive for VLCAD deficiency with C14:1 and C14:1/C2 ratios. Our analyses indicated that the ratios of C14:1 to medium-chain acylcarnitines (C10, C8, and C6) were the most effective markers in reducing false-positive rates. Their use with appropriate cutoffs is expected to improve NBS performance for VLCAD deficiency.

Understanding patient, caregiver, and healthcare provider perspectives of the management of long-chain fatty acid oxidation disorders.

Long-chain fatty acid oxidation disorders (LC-FAODs) are a group of rare, inherited, metabolic disorders that can lead to a wide range of symptoms that predominantly affect organ systems with high energy needs, such as the heart, liver, skeletal muscle, and nervous system. Clinical management primarily consists of close attention to and monitoring of diet and activity and avoidance of prolonged fasting. In addition, patients and caregivers must be alert for signs of life-threatening metabolic decompensation. As a result, LC-FAODs can have significant and wide-ranging impacts on the lives of patients and their caregivers. This article describes the effects of LC-FAODs at different life stages and in the context of the North American healthcare system from the perspective of a group of patients, caregivers, and healthcare providers (n = 6). We explain how challenges and needs change throughout life. Following an early diagnosis, an adjustment phase occurs during which caregivers may feel overwhelmed by their new roles and deeply concerned for their children's futures. As children grow, they become more aware of the differences between themselves and their peers, and with increasing independence comes more responsibility for managing their own condition. Major life events, such as new employment and moving house, pose challenges for people of all ages. In addition, it may be difficult to find and connect with qualified and experienced healthcare providers; navigate the health insurance system; and educate and align primary, specialist, and emergency care providers. We propose several strategies to improve the care of patients with LC-FAODs, such as educating local healthcare teams, improving trust between patients/caregivers and healthcare providers, and raising awareness of the challenges faced by patients and caregivers across the different life stages.

18 Months of Treatment with Triheptanoin in 2 Patients with Long Chain Fatty Acid Oxidation Disorders

Introduction:: Long-chain fatty acid oxidation disorders (LC-FAOD) are inborn errors of metabolism, also identified in newborn screening in Portugal. They interfere with adequate energy utilization, namely by muscles, heart, and liver. Treatment aims to maintain patients in an anabolic state, with increased caloric intake, using carbohydrates and medium-chain fatty acids. Treatment with triheptanoin (THP), a synthetic seven-carbon fatty acid triglyceride compound with an anaplerotic effect that increases energy availability to the cell, has been advocated as an efficacious and safe therapy in LC-FAOD. Methods:: Retrospective revision of clinical records of 2 LC-FAOD patients comparing number, severity and admissions for rhabdomyolysis crises, maximum CK values and weight gain in a period of 18 months before and after treatment with THP. Results/Case Report:: Patient 1 is a 12 year old male with VLCADD, with main manifestation being rhabdomyolysis crises. After he started THP we found a decrease in admissions (6 to 2), less rhabdomyolysis crises treated at home (5 to 3), and lower maximum CK values (72352 U/L to 13.000U/L). He had a large increase in weight - 13kg in 18 months. He was able to start pool exercises with no rhabdomyolysis associated. Patient 2 is an 8 year old male with LCAHDD, with main manifestations being rhabdomyolysis crises and retinopathy. After he started THP we found a decrease in admissions (4 to 1), no rhabdomyolysis crises treated at home, and lower maximum CK values (100.000U/L to 19848 U/L). He also increased his weight - 7kg in 18 months. He plays football in school and swims with no rhabdomyolysis associated. In both patients, no major side effects were observed. Conclusion:: In our patients, we could observe a reduction in the number of admissions, and less severe rhabdomyolysis crises after THP use. The weight gain was significant. There were no major side effects. Despite regarding only two patients, our findings are in line with the latest literature on THP and LC-FAOD, reinforcing the utility of THP as one more tool in the treatment of these disorders with rhabdomyolysis as the main manifestation. The weight increase is an issue to be aware of and to address from the start of the treatment.

Psychosocial issues and coping strategies in families affected by long-chain fatty acid oxidation disorders.

Long-chain fatty acid oxidation disorders (lcFAODs) are associated with a high disease burden due to both the risk of metabolic decompensation as well as chronic, partly irreversible complications in some. Little research has been performed on the impact of these disorders on the daily life of parents and caregivers. We performed a web-based questionnaire study among parents/caregivers of patients affected with lcFAODs. The questionnaire focused on challenges at different ages of the child, on disease management issues, schooling, family and social life as well as the parental job situation, and their overall attitude toward the disease and the future life of their child. Data were collected from parents/caregivers of 63 patients (87 respondents, 63% mothers, 36% fathers) with lcFAODs (median age of patients 8.0 years, range 0-25 years, long-chain 3-hydrocyacyl-CoA dehydrogenase deficiency 40%, mitochondrial trifunctional protein deficiency 14%, very long-chain acyl-CoA dehydrogenase deficiency 41%, carnitine palmitoyltransferase 2 deficiency 5%). The overall disease burden of parents was considered highest during infancy and decreased with increasing age of their child. More than one third of parents were afraid that their child's disease might have an impact on his/her career choice and adult life. Negative effects of the child's disease on the job situation and career development were more commonly reported by mothers compared to fathers. Although the majority of parents considered their child's metabolic disorder a severe disease, most parents had a positive attitude toward their child's disease and seemed to cope well with their situation.

Micronutrient Deficiency in Inherited Metabolic Disorders Requiring Diet Regimen: A Brief Critical Review

Many inherited metabolic disorders (IMDs), including disorders of amino acid, fatty acid, and carbohydrate metabolism, are treated with a dietary reduction or exclusion of certain macronutrients, putting one at risk of a reduced intake of micronutrients. In this review, we aim to provide available evidence on the most common micronutrient deficits related to specific dietary approaches and on the management of their deficiency, in the meanwhile discussing the main critical points of each nutritional supplementation. The emerging concepts are that a great heterogeneity in clinical practice exists, as well as no univocal evidence on the most common micronutrient abnormalities. In phenylketonuria, for example, micronutrients are recommended to be supplemented through protein substitutes; however, not all formulas are equally supplemented and some of them are not added with micronutrients. Data on pyridoxine and riboflavin status in these patients are particularly scarce. In long-chain fatty acid oxidation disorders, no specific recommendations on micronutrient supplementation are available. Regarding carbohydrate metabolism disorders, the difficult-to-ascertain sugar content in supplementation formulas is still a matter of concern. A ketogenic diet may predispose one to both oligoelement deficits and their overload, and therefore deserves specific formulations. In conclusion, our overview points out the lack of unanimous approaches to micronutrient deficiencies, the need for specific formulations for IMDs, and the necessity of high-quality studies, particularly for some under-investigated deficits.

Abstract 15278: Cardiac Assessments and Manifestations Among Individuals With Long-Chain Fatty Acid Oxidation Disorders: A Retrospective Claims Database Analysis

Introduction: Long-chain fatty acid oxidation disorders (LC-FAOD) are inherited autosomal recessive defects resulting in enzyme deficiencies in the carnitine cycle or the mitochondrial β-oxidation pathway leading to deficiencies in mitochondrial energy metabolism. Cardiac manifestations, specifically cardiomyopathy and arrhythmias, are common and are leading causes of mortality in individuals with LC-FAOD. Goal: The goal of this study was to better understand cardiac manifestations and long-term outcomes in this group of disorders. Methods: The analysis was done using IQVIA PharMetrics® claims data. Individuals with confirmed LC-FAOD were identified and a non-LC-FAOD comparators group was created using 1:20 exact matching on age, gender, payer type, and enrollment start year. Cardiac-related complications were examined using ICD-10 diagnosis codes at any billing position during the study period. Cardiac diagnoses and assessments were evaluated using Current Procedural Terminology (CPT®) codes in a non-inpatient setting. Results: A total of 337 pediatric (peds) and 86 adult individuals with LC-FAOD were included in the study. Cardiomyopathy (peds: 8.0%, adults: 10.5%) and arrhythmias (peds: 8.9%, adults: 14.0%) were common among individuals with LC-FAOD and were significantly higher than comparators. LC-FAOD adults had significantly more cardiac conditions compared with pediatric patients and comparators. The other most common cardiac conditions among adults with LC-FAOD were chronic ischemic heart disease (18.6%), non-rheumatic mitral or tricuspid valve disorders (11.6% and 12.8%, respectively), heart failure (10.5%), atrioventricular and left bundle-branch block (7.0%), and cardiomegaly (5.1%). Individuals with LC-FAOD had significantly more cardiac related procedures than comparators. EKGs (peds: 35.9%; adults: 77.9%) and echocardiograms (peds: 44.8%; adults: 53.5%) were common among individuals with LC-FAOD. Conclusions: This analysis shows the importance of assessing the cardiac status of individuals with LC-FAOD. More analyses and natural history studies are needed to inform healthcare providers of cardiac risks associated with LC-FAOD and reduce mortality in these individuals.

Newborn Screening with (C16 + C18:1)/C2 and C14/C3 for Carnitine Palmitoyltransferase II Deficiency throughout Japan Has Revealed C12/C0 as an Index of Higher Sensitivity and Specificity.

Carnitine palmitoyltransferase (CPT) II deficiency is a long-chain fatty acid oxidation disorder. It manifests as (1) a lethal neonatal form, (2) a hypoglycemic form, or (3) a myopathic form. The second form can cause sudden infant death and is more common among Japanese people than in other ethnic groups. Our study group had earlier used (C16 + C18:1)/C2 to conduct a pilot newborn screening (NBS) study, and found that the use of C14/C3 for screening yielded lower rates of false positivity; in 2018, as a result, nationwide NBS for CPT II deficiency started. In this study, we evaluated the utility of these ratios in 71 NBS-positive infants and found that the levels of both C14/C3 and (C16 + C18:1)/C2 in patients overlapped greatly with those of infants without the disease. Among the levels of acylcarnitines with various chain lengths (C18 to C2) and levels of free carnitine (C0) as well as their ratios of various patterns, C12/C0 appeared to be a promising index that could reduce false-positive results without missing true-positive cases detected by current indices. Although some cases of the myopathic form may go undetected even with C12/C0, its use will help prevent life-threatening onset of the hypoglycemic form of CPT II deficiency.

PCR226 Symptoms, Treatment Effectiveness and Quality of Life for Patients Living with Long-Chain Fatty Acid Oxidation Disorders (LC-FAOD) in the United States: Patient and Caregiver Reported Outcomes from LC-FAOD Odyssey

The LC-FAOD Odyssey study collects medical record data and prospective patient- and caregiver-reported outcomes (PROs). Data are used to assess the real-world impact of LC-FAOD and treatment effectiveness.

Resting and total energy expenditure of patients with long-chain fatty acid oxidation disorders (LC-FAODs).

The basis of medical nutrition therapy for patients with LC-FAODs is to provide adequate energy to maintain anabolism and prevent catabolism. In practice, energy needs are estimated based on formulas derived from normal populations but it is unknown if energy expenditure among patients with LC-FAODs is similar to the normal population. We measured resting energy expenditure (REE), total energy expenditure (TEE) and body composition in 31 subjects with LC-FAODs ranging in age from 7 to 64 years. Measured REE was lower than estimated REE by various prediction equations and measured TEE was lower than estimated TEE. It is possible that the lower energy expenditure based on prediction formulas from the normal population is due to differences in body composition; we compared body composition to normal data from the 2017-18 National Health and Nutrition Examination Survey (NHANES). Fat free mass and fat mass was similar between subjects with an LC-FAOD and NHANES normal data suggesting no difference in body composition. We then compared measured REE and TEE to normal published data from the Dietary Reference Intakes (DRI). Measured REE and TEE were significantly lower among subjects with LC-FAODs compared to normal published energy expenditure data. Our results suggests patients with a LC-FAOD exhibit a lower REE and therefore actually have a slightly lower TEE than estimated. Current prediction equations may overestimate energy expenditure of patients with a LC-FAOD.

P041: Real-world major clinical events and healthcare resource use among patients with long-chain fatty acid oxidation disorders in the United States

P041: Real-world major clinical events and healthcare resource use among patients with long-chain fatty acid oxidation disorders in the United States

P276: Long-chain fatty acid oxidation disorder genotypes, clinical signs and symptoms, and newborn screening history from a gene panel sponsored program

P276: Long-chain fatty acid oxidation disorder genotypes, clinical signs and symptoms, and newborn screening history from a gene panel sponsored program