Fasting Tolerance in MCADD-infants

Study Overview
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Brief Summary
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MCAD deficiency (MCADD; #OMIM 201450) is the most common inherited disorder of mitochondrial fatty acid oxidation. Already before the introduction of population newborn bloodspot screening (NBS), large phenotypic heterogeneity was observed between MCADD-patients, ranging between deceased patients and asymptomatic subjects. Most clinically ascertained patients were homozygous for the common c.985A>G ACADM mutation. After NBS, newborns with novel ACADM-genotypes have been identified and subjects can be classified as either severe/classical or mild/variant MCADD-patients. Dietary management guidelines are based on expert opinion, limited experimental data summarized in one retrospective study on fasting tolerance in 35 MCADD patients. Interestingly, data are absent from fasting tolerance in MCADD patients between 0-6 months of age. These guidelines cause parental stress, especially for young patients. Moreover, the guidelines do not take into account the heterogeneity between patients, including the classification between severe versus mild MCADD-patients. The investigators question whether at least a subset of the MCADD-patients is overtreated with these guidelines. Therefore, the investigators propose this pilot-study on fasting tolerance in 10 subjects with severe MCADD and 10 subjects with mild MCADD at the ages of two and six months. Differences between subsets of MCADD-patients will be studied longitudinally by both traditional metabolic parameters and unbiassed metabolomics, lipidomics and proteomics approach. This project will substantiate current management guidelines and aims to identify new (prognostic) biomarkers.

Detailed Description
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Rationale: MCAD deficiency (MCADD; #OMIM 201450) is the most common inborn error of mitochondrial fatty acid oxidation. Already before the introduction of population newborn bloodspot screening (NBS), large phenotypic heterogeneity was observed between MCADD patients, ranging between deceased patients and asymptomatic subjects. Most clinically ascertained patients were homozygous for the common c.985A>G ACADM mutation. After the introduction of the disorder to the NBS, newborns with novel ACADM-genotypes have been identified. Subjects can be classified as either severe/classical or mild/variant MCADD patients. Dietary management guidelines are based on expert opinion and limited experimental data summarized in one retrospective study on fasting tolerance in 35 MCADD-patients. Interestingly, data are absent from the fasting tolerance of MCADD patients between 0-6 months of age. These guidelines cause parental stress, especially regarding young patients (0-6 months). Moreover, the guidelines do not take into account the heterogeneity between patients, including the classification between severe versus mild MCADD patients. The investigators question whether at least a subset of the MCADD patients is overtreated with these guidelines. Objective: The main objective of the study is to explore the fasting tolerance in MCADD-patients of two and six months of life. Second, it is aimed to compare fasting tolerance and biochemical dynamics between subsets of MCADD patients. Third, it is aimed to identify novel diagnostic and/or prognostic biomarkers. The last objective is to elucidate the (fundamental) origin of phenotypical differences between MCADD patients. Study design: Longitudinal, prospective investigator-initiated human pilot-study. Study population: Otherwise healthy infants with severe MCADD and mild MCADD at the ages of two and six months of life. Intervention: During two visits, the included infants will be fasted according to local standardized procedures at the University Medical Centre Groningen (UMCG). Fasting will take place under continuous blood glucose monitoring and bedside supervision by an experienced, dedicated pediatric nurse in collaboration with a metabolic pediatrician, who will be available to attend the patient instantly. During visit 1, at two months of life, fasting will be continued for maximally eight hours. During visit 2, at six months of life, fasting will be continued for maximally twelve hours. Fasting will be ended prematurely if; (a) the blood glucose concentration drops < 3.6 mmol/L, (b) the fasting subject shows symptoms/signs of a low blood glucose concentration, and/or (c) subject's parent(s) or guardian(s) request the end of fast. Main study parameters/endpoints: Dynamics of both traditional clinical and biochemical metabolic parameters and unbiased multi-omics (metabolomics, lipidomics, and proteomics) parameters will be studied. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The trial is considered to be a low-risk study. The clinical research team at the UMCG has a longstanding tradition of performing supervised controlled clinical fasting test in patients with inborn errors of metabolism, for diagnostic as well as research purposes. No adverse effects are expected during fasting in otherwise healthy infants with MCADD. The study holds three moderate burdens for participants: insertion of the indwelling IV catheter, the discomfort of fasting for the subject and the parent(s) or guardian(s), and the time consumption. However, subjects and their parents(s) may directly benefit from the results of this study by reduction of stress concerning feeding, under normal, healthy circumstances and the (possible) institution of a personalized feeding regimen based on the study results by the treating pediatrician. As this project will substantiate current management guidelines and aims to identify new (prognostic) biomarkers, it may further improve the outcomes of future MCADD patients and their parent(s) or guardian(s), by reduction of (unnecessary) parental stress, treatment and follow-up.

Official Title
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Fasting Tolerance in Patients With Medium-chain Acyl-CoA Dehydrogenase Deficiency (MCADD) in the First Six Months of Life: an Investigator-initiated Human Pilot-study

Conditions
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Mcad Deficiency

Intervention / Treatment
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* Other: Fasting test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: A child must be at least younger than 6 months of life at inclusion. In case of prematurity, the child will be included and treated according to the adjusted age. Established MCADD diagnosis. The diagnosis should be confirmed by a combination of (a) NBS outcome (b) MCAD enzyme activity measured with phenylpropionyl-CoA as a substrate, ideally in lymphocytes (considered to be the golden standard) and (c) ACADM gene mutation-analysis. Exclusion Criteria: Any other chronic and/or genetic condition that is deemed an exclusion criterion based on the judgement of the treating metabolic paediatrician.

Ages Eligible for Study
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Minimum Age: 2 Months
Maximum Age: 6 Months

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Severe/classical MCADD<br>Severe MCADD will be defined by ACADM mutations associated with clinical ascertainment or residual MCAD enzyme activity < 10 %, as defined previously (Touw et al., 2012). Interventions include fasting challenges at two and six months of age. | Other: Fasting test<br>* The included infants will be fasted according to local standardized procedures at the University Medical Centre Groningen. Fasting will take place under hourly blood glucose monitoring and bedside supervision by an experienced, dedicated pediatric nurse, in collaboration with a metabolic pediatrician, who will be available to attend the patient instantly. Furthermore, on request of parent(s) or guardian(s), a continuous blood glucose monitoring device can be used during the study visits. During study visit 1, at two months of life, fasting will be continued for maximally eight hours. During study visit 2, at six months of life, fasting will be continued for maximally twelve hours. Fasting will be ended prematurely in the following events: blood glucose concentration drops < 3.6 mmol/L; the child shows symptoms/signs of a low blood glucose concentration; patients parent(s) or guardian(s) request end of fast.<br>|
| Experimental: Mild MCADD<br>Mild MCADD will be defined by the remaining ACADM genotype variants and residual MCAD enzyme activity ≥ 10%. Interventions include fasting challenges at two and six months of age. | Other: Fasting test<br>* The included infants will be fasted according to local standardized procedures at the University Medical Centre Groningen. Fasting will take place under hourly blood glucose monitoring and bedside supervision by an experienced, dedicated pediatric nurse, in collaboration with a metabolic pediatrician, who will be available to attend the patient instantly. Furthermore, on request of parent(s) or guardian(s), a continuous blood glucose monitoring device can be used during the study visits. During study visit 1, at two months of life, fasting will be continued for maximally eight hours. During study visit 2, at six months of life, fasting will be continued for maximally twelve hours. Fasting will be ended prematurely in the following events: blood glucose concentration drops < 3.6 mmol/L; the child shows symptoms/signs of a low blood glucose concentration; patients parent(s) or guardian(s) request end of fast.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in blood glucose concentrations | Sample #1 will be collected at baseline (8:00 AM) and hereafter hourly during the fast of session 1 and session 2. | Up to 8 samples will be taken during the maximally 8 hour fast (session 1), up to 12 samples will be taken during the maximally 12 hour fast (session 2). | 
| Change in plasma free fatty acid (FFA) concentrations | Sample #1 will be collected at baseline (8:00 AM) and here-after hourly during the fast of session 1 and session 2. | Up to 8 samples will be taken during the maximally 8 hour fast (session 1), up to 12 samples will be taken during the maximally 12 hour fast (session 2). | 
| Change in Heart rate | Heart rate per minute will be noted at baseline (8:00 AM) and here-after hourly during the fast of session 1 and session 2. | Up to 8 frequencies will be noted during the maximally 8 hour fast (session 1), up to 12 frequencies will be noted during the maximally 12 hour fast (session 2) | 
| Change in Respiratory rate | Respiratory rate per minute will be noted at baseline (8:00 AM) and here-after hourly during the fast of session 1 and session 2. | Up to 8 frequencies will be noted during the maximally 8 hour fast (session 1), up to 12 frequencies will be noted during the maximally 12 hour fast (session 2). | 
| (Change in) presence of lethargy | Physical examination will be performed hourly by a nurse during the fast of session 1 and session 2. Yes/no; if yes, #hours, minutes. | Up to 8 physical examinations will be performed during the maximally 8 hour fast (session 1), up to 12 physical examinations will be performed during the maximally 12 hour fast (session 2). Physical examinations will take 5 minutes. | 
| (Change in) presence of trembling | Physical examination will be performed hourly by a nurse during the fast of session 1 and session 2. Yes/no; if yes, #hours, minutes. | Up to 8 physical examinations will be performed during the maximally 8 hour fast (session 1), up to 12 physical examinations will be performed during the maximally 12 hour fast (session 2). Physical examinations will take 5 minutes. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Continuous glucose monitoring (CGM) data | Subcutaneous glucose concentrations will be obtained with a Dexcom G6 CGM sensor, if used. | Blood glucose concentrations will be sensored every 5 minutes, during the maximally 8 hour fast (session 1). Blood glucose concentrations will be sensored every 5 minutes, during the 12 hour fast (session 2). | 
| Blood pH | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (#hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| Blood oxygen partial pressure | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (#hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| Blood carbon dioxide partial pressure | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (#hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| Plasma bicarbonate concentrations | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (#hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| Base excess | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (#hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| Blood oxygen saturation | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (#hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the 12 hour fast (session 2). | 
| Plasma ketones concentrations (β-hydroxybutyrate, acetoacetate) | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| Plasma acylcarnitines concentrations | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| Plasma amino acid concentrations | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (#hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| Urine organic acids concentrations | During session 1, sample #1 will be collected during the first 6 hours of the maximally 8 hours fast. Sample #2 will be collected during the last 2 hours of the maximally 8 hour fast. During session 2, sample #1 will be collected during the first 10 hours of the maximally 12 hour fast. Sample 2 will be collected during the last 2 hours of the maximally 12 hour fast. | 2 samples will be collected during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| (Untargeted) Metabolomics | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (#hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| Lipidomics | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (#hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the maximally 12 hour fast (session 2). | 
| Proteomics | Sample #1 will be collected at baseline (start fast, 8:00 AM), sample #2 will be collected 2 hours after the start of the fast (10:00 AM), sample #3 will be taken at the end of the fast after maximally 8 hours (16:00, session 1) or 12 hours (20:00, session 2), or earlier if necessary (#hours, minutes). | 3 samples will be taken during the maximally 8 hour fast (session 1) and during the 12 hour fast (session 2). | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Mcad deficiency, Phenotypic Variation, Biomarkers, Diet Therapy