Paeds · genetics-dysmorphology-and-metabolism
Hypoglycaemia due to inherited metabolic disease
Also known as Metabolic hypoglycaemia · Hypoketotic hypoglycaemia · Congenital hyperinsulinism · CHI · Fatty acid oxidation defect with hypoglycaemia · MCAD deficiency · Glycogen storage disease type I · GSD Ia
A fellowship approach to hypoglycaemia caused by inherited metabolic disease: recognise the fasted or febrile child with hypoketotic hypoglycaemia, seizures or hepatomegaly as an emergency, capture the critical sample before treating, then work through the three physiological failures — insulin-driven (congenital hyperinsulinism), glucose-production failure (glycogen storage disease, fructose-1,6-bisphosphatase deficiency), and fuel-oxidation block (fatty-acid oxidation defects) — each with its own acute and lifelong management.
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Target exams
Red flags
- Any neonate, infant, or child with symptomatic hypoglycaemia provoked by fasting or intercurrent illness — send a critical sample before correcting glucose if it is safe to do so
- Hypoketotic hypoglycaemia (low beta-hydroxybutyrate relative to the degree of glucose depression) — the cardinal clue to a fatty-acid oxidation defect or hyperinsulinism
- A previously well child found comatose, seizing, or dead after a period of fasting, particularly with hepatomegaly or cardiomyopathy — think medium-chain acyl-CoA dehydrogenase deficiency
- Recurrent or severe hypoglycaemia unresponsive to physiological glucose infusion rates, or needing more than 10–12 mg/kg/min of glucose — points to congenital hyperinsulinism
- Macrosomic or large-for-gestational-age neonate with persistent hypoglycaemia and high insulin requirement beyond 48 hours — congenital hyperinsulinism, including Beckwith-Wiedemann
- Hypoglycaemia with lactic acidosis, hyperuricaemia and hepatomegaly — glycogen storage disease type I
- A family history of sudden infant death, unexplained sibling death, or consanguinity alongside recurrent hypoglycaemia
Life stages
Care settings
Clinical exam formats
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- Recognition and emergency management of hypoglycaemia in infants and children
- The critical sample and its interpretation
- Hypoketotic hypoglycaemia as a metabolic red flag
- Pathophysiology and classification of inherited causes of hypoglycaemia
- Congenital hyperinsulinism genetics and management including diazoxide, sirolimus and surgery
- Fatty-acid oxidation defects and glycogen storage disease long-term care
- Stabilising a hypoglycaemic neonate or child and interpreting the critical sample
- Differentiating hyperinsulinism from fatty-acid oxidation defects and glycogen storage disease
- Counselling a family on an inherited hypoglycaemia diagnosis and recurrence risk
- Acute case of an infant presenting with hypoketotic hypoglycaemia and seizures
- Long case of a child with congenital hyperinsulinism discussing diazoxide, sirolimus, near-total pancreatectomy and neurodevelopmental outcome
- Metabolic and endocrine causes of hypoglycaemia
- Investigation of the acutely unwell child
- Neonatal hypoglycaemia beyond transitional hyperinsulinaemia
- Physiology of glucose homeostasis and ketogenesis
- Critical-sample interpretation in childhood hypoglycaemia
- Genetics of congenital hyperinsulinism and fatty-acid oxidation defects
- Resuscitation of the hypoglycaemic collapse
- Communicating a lifelong inherited metabolic diagnosis to parents
- Inborn errors of metabolism presenting as hypoglycaemia
- Congenital hyperinsulinism diagnosis and management
- Medium-chain acyl-CoA dehydrogenase deficiency and the risk of sudden death
- Inherited hypoglycaemic disorders
- Acute hypoglycaemic emergencies
- Multidisciplinary care of congenital hyperinsulinism and fatty-acid oxidation defects
- Inherited causes of childhood hypoglycaemia
- Critical-sample evaluation and emergency management
- Long-term outcomes of congenital hyperinsulinism
The fellowship mark goes to the candidate who works in three layers at once. The first is the child in front of you — an encephalopathic neonate or a seizing infant — where the immediate questions are the glucose, the ketones, and the critical sample, not the gene. The second is the physiology: glucose homeostasis is a balance between supply and utilisation, and ketones are the brain's alternate fuel when glucose falls, so a child who cannot make ketones is doubly exposed. The third is the family: a monogenic cause such as congenital hyperinsulinism or a fatty-acid oxidation defect carries a recurrence risk, a risk to siblings, and a lifelong management obligation that begins moment diagnosis is named. [1] [2]
Overview & Definition
Hypoglycaemia due to inherited metabolic disease is a low blood glucose caused by a genetically determined failure of one of the metabolic pathways that maintain the blood sugar during fasting. The threshold that should trigger investigation is a plasma glucose below roughly 2.6 to 3.0 millimoles per litre in a symptomatic child, with the Pediatric Endocrine Society recommending a structured evaluation of any child with persistent or recurrent hypoglycaemia rather than accepting a single normal value. The inherited causes matter because they are recurrent, potentially lethal, and — uniquely among the causes of hypoglycaemia — they offer a disease-specific treatment once the diagnosis is made. [1]
Clinically, these disorders sit within the family of intoxication-type and energy-failure-type inborn errors of metabolism: conditions in which a blocked pathway produces either a toxic accumulation or an energy deficit that is itself the disease. The framing matters because it dictates management — the priority is to restore substrate and capture the diagnostic window during the decompensation, because the abnormal metabolites and hormone profile are only visible while the child is hypoglycaemic. Once glucose is corrected the biochemical fingerprint disappears, which is why a missed critical sample can delay the diagnosis for years. [9] [10]
References12ShowHide
- [1]Thornton PS, Stanley CA, De Leon DD, Harris D, Haymond MW, Hussain K, et al. Recommendations from the Pediatric Endocrine Society for Evaluation and Management of Persistent Hypoglycemia in Neonates, Infants, and Children. J Pediatr, 2015.PMID 25957977
- [2]Kapoor RR, Flanagan SE, Arya VB, Shield JPH, Ellard S, Hussain K. Clinical and molecular characterisation of 300 patients with congenital hyperinsulinism. Eur J Endocrinol, 2013.PMID 23345197
- [3]Snider KE, Becker S, Boyajian L, Shyng SL, MacMullen C, Hughes N, et al. Genotype and phenotype correlations in 417 children with congenital hyperinsulinism. J Clin Endocrinol Metab, 2013.PMID 23275527
- [4]Chou JY, Jun HS, Mansfield BC. Glycogen storage disease type I and G6Pase-β deficiency: etiology and therapy. Nat Rev Endocrinol, 2010.PMID 20975743
- [5]Koeberl DD, Koch RL, Lim JA, et al. Gene therapy for glycogen storage diseases. J Inherit Metab Dis, 2024.PMID 37421310
- [6]Spiekerkoetter U, Bastin J, Gillingham M, et al. Current issues regarding treatment of mitochondrial fatty acid oxidation disorders. J Inherit Metab Dis, 2010.PMID 20830526
- [7]Wanders RJA, Visser G, Ferdinandusse S, et al. Mitochondrial Fatty Acid Oxidation Disorders: Laboratory Diagnosis, Pathogenesis, and the Complicated Route to Treatment. J Lipid Atheroscler, 2020.PMID 33024728
- [8]Stanley CA. Carnitine deficiency disorders in children. Ann N Y Acad Sci, 2004.PMID 15591002
- [9]Saudubray JM, Garcia-Cazorla À. Inborn Errors of Metabolism Overview: Pathophysiology, Manifestations, Evaluation, and Management. Pediatr Clin North Am, 2018.PMID 29502909
- [10]Saudubray JM, Mochel F, Lamari F, et al. Proposal for a simplified classification of IMD based on a pathophysiological approach: A practical guide for clinicians. J Inherit Metab Dis, 2019.PMID 30883825
- [11]Douillard C, Mention K, Dobbelaere D, Wemeau JL, Saudubray JM, Vantyghem MC. Hypoglycaemia related to inherited metabolic diseases in adults. Orphanet J Rare Dis, 2012.PMID 22587661
- [12]Garg M, Devaskar SU. Exploring the long-term impacts of neonatal hypoglycemia to determine a safe threshold for glucose concentrations. Eur J Pediatr, 2025.PMID 40119223