Mauriac Syndrome: Isotopic Techniques and Genetic Analysis

Study Overview
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Brief Summary
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Mauriac syndrome (MS) is an entity of individuals combining poorly controlled diabetes mellitus type 1, short stature and glycogenic hepatopathy. Thus, the functional significance of Mauriac syndrome for glucose metabolism remains disputed, and whether genetic defects in glycogen metabolism contribute to glycogenic hepatopathy in MS remains to be clarified.Coupling the genetic analysis of targeted genes involved in glucose regulation with a dynamic exploration will eventually determine if a genetic abnormality leads to the disease and explains the nature of the phenotype.

Detailed Description
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Investigation of glucose homeostasis in MS, after an oral glucose load followed by exercise, using a quantitative measurement of the substrate flux. This dynamic in vivo kinetics can be explored using stable, nonradioactive tracers with the help of gas or liquid chromatography. Investigation of genetic factors associated with MS phenotype. Molecular analysis will be performed by next generation sequencing (exome or whole genome sequencing). In addition, a targeted analysis for pathogenic variants in genes implicated in homeostasis regulation will be done.

Official Title
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Genetic Analysis Coupled to Application of Isotopic Techniques to the Study of Mauriac Syndrome

Conditions
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Diabetes Mellitus, Short Stature, Glycogen Deposition

Intervention / Treatment
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* Other: oral glucose load
* Other: exercise test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Inclusion criteria for controls: DT1 > 18 years old) Presence of at least one of the following auto-antibodies: anti-GAD65, anti-IAA, anti-ZnT8, anti-IA2 or ICA and/or low C-Peptide Insulin therapy by multiple daily injections or continuous subcutaneous insulin infusion by an insulin pump Informed consent as documented by signature Inclusion criteria for subjects: Mauriac syndrome DT1 > 18 years old Presence of hepatomegaly in infancy (confirmed ≥ 1 abdominal US) at the time of diagnosis of Mauriac Syndrome Presence of short stature during infancy at the time of diagnosis of Mauriac Syndrome (<P3; WHO growth curves on ≥ 2 different measures, at 2 different time-points) Presence of at least one of the following auto-antibodies: anti-GAD65, anti-IAA, anti-ZnT8, anti-IA2 or ICA and/or low C-Peptide Informed consent as documented by signature Exclusion criteria for subjects and controls : Obesity (BMI ≥ 30 kg/m2 or > 90th percentile) Illness that contraindicates physical activity Women who are pregnant or breast feeding Any clinically unstable disease Myocardial infarcts, syncope, heart rhythm disorder, unstable hypertension in the last 6 months Blood donation in the last 3 months for men and 4 months for women before the study Enrollment in a previous study less than 30 days before the start of the study Participation of the investigator, a family member, an employee or someone having a link with the investigator

Ages Eligible for Study
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Minimum Age: 18 Years

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: Other
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Case control study
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Mauriac syndrome<br>An oral dose of glucose (labelled with 1% U-13C6-glucose) will be given at time 0 min followed by a 30-min cycling exercise at time 300 min. | Other: oral glucose load<br>* oral glucose load (60g) followed by exercise at fixed wattage (60W) for 30 min<br>Other: exercise test<br>* oral glucose load (60g) followed by exercise at fixed wattage (60W) for 30 min<br>|
| Other: Type 1 diabetes mellitus<br>An oral dose of glucose (labelled with 1% U-13C6-glucose) will be given at time 0 min followed by a 30-min cycling exercise at time 300 min. | Other: oral glucose load<br>* oral glucose load (60g) followed by exercise at fixed wattage (60W) for 30 min<br>Other: exercise test<br>* oral glucose load (60g) followed by exercise at fixed wattage (60W) for 30 min<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| In vivo kinetics of ingested glucose | Plasma glucose kinetics [Time -90 min before ingestion of a test meal to Time 360 min after ingestion of a test meal] Baseline : [Time -90min to Time 0min] After an oral glucose load (60g): [Time 0min to Time 300min] During exercise at fixed wattage (60W) for 30 min: [Time 300 min to Time 330 min] After exercise for 30 min [Time 330 min to Time 360 min] Trial stable isotope tracers ([U-13C6] glucose ingestion, will be used to assess ingested glucose flux at baseline and during the test. | Time -90 minutes to Time 360 minutes | 
| In vivo kinetics of endogenous glucose | Plasma glucose kinetics [Time -90 min before ingestion of a test meal to Time 360 min after ingestion of a test meal] Baseline : [Time -90min to Time 0min] After an oral glucose load (60g): [Time 0min to Time 300min] During exercise at fixed wattage (60W) for 30 min: [Time 300 min to Time 330 min] After exercise for 30 min [Time 330 min to Time 360 min] Trial stable isotope tracers [6,6-2H2] glucose infusion will be used to assess endogenous glucose flux at baseline and during the test. | Time -90 minutes to Time 360 minutes | 
| In vivo kinetics of lactate | Plasma lactate kinetics [Time -90 min before ingestion of a test meal to Time 360 min after ingestion of a test meal] Baseline : [Time -90min to Time 0min] After an oral glucose load (60g): [Time 0min to Time 300min] During exercise at fixed wattage (60W) for 30 min: [Time 300 min to Time 330 min] After exercise for 30 min [Time 330 min to Time 360 min] Trial stable isotope tracers [1-13C1]lactate infusion will be used to assess lactate flux at baseline and during the test. | Time -90 minutes to Time 360 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| DNA Banking | 10 ml of whole blood will be collected, at baseline, in two tubes EDTA 5ml for DNA extraction and banking in view of next generation sequencing (NGS) analysis. | At inclusion period |