Journal of Inherited Metabolic Disease

, Volume 32, Issue 2, pp 214–217

Tolerance to fast: rational and practical evaluation in children with hypoketonaemia


    • Willink Biochemical Genetics UnitRoyal Manchester Children’s Hospital
SSIEM Symposium 2008

DOI: 10.1007/s10545-009-1087-y

Cite this article as:
Walter, J.H. J Inherit Metab Dis (2009) 32: 214. doi:10.1007/s10545-009-1087-y


Prolonged fasting in children with disorder of fat oxidation or ketone body synthesis can lead not only to hypoglycaemia but also to the accumulation of toxic metabolites. The length of time such patients can be safely fasted is important information for caregivers. Most children with MCAD deficiency when well can tolerate ‘normal’ periods without food, but in more severe disorders such as LCHAD deficiency even these may be associated with acute or chronic damage. Guidelines have been published for safe fasting periods in MCAD but not in other conditions. In the absence of such recommendations, a rational approach must be based on an understanding of the normal physiology of fasting in children of different ages and the pathophysiology associated with the child’s particular disorder. Intercurrent infections pose a particular risk and may significantly reduce fasting tolerance.



long-chain hydroxyacyl-CoA dehydrogenase


medium-chain acyl-CoA dehydrogenase


medium-chain triglycerides


very long-chain acyl-CoA dehydrogenase

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© Springer Science+Business Media B.V. 2009