Dihydrolipoamide Dehydrogenase Deficiencies and Associated Metabolic Disorders

Dihydrolipoamide dehydrogenase (DLD) deficiency is an autosomal recessive mitochondrial disorder caused by pathogenic variants in the gene encoding the E3 subunit common to multiple α-ketoacid dehydrogenase complexes and the glycine cleavage system. Loss of DLD activity impairs pyruvate dehydrogenase, α-ketoglutarate dehydrogenase and branched-chain α-ketoacid dehydrogenase function, resulting in accumulation of pyruvate, lactate and branched-chain amino acid intermediates. Clinically, this manifests as lactic acidosis, neurodevelopmental delay, seizures, cardiomyopathy, hepatic dysfunction and, in severe neonatal cases, early mortality. Molecular defects often disrupt enzyme homodimer assembly, flavin adenine dinucleotide binding and catalytic turnover, while secondary overproduction of reactive oxygen species exacerbates tissue injury. The marked variability in presentation and the absence of curative therapies have spurred development of preclinical models and exploration of cofactor and small-molecule interventions. Growing insight into structure–function relationships and pathomechanisms promises personalised therapeutic strategies and underscores the global significance of this rare but instructive multisystem metabolic disorder.

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Dihydrolipoamide Dehydrogenase Deficiencies and Associated Metabolic Disorders publication trend

The graph below shows the total number of articles in dihydrolipoamide dehydrogenase deficiencies and associated metabolic disorders across all publications each year (not limited to Nature Index journals).

Technical terms

Dihydrolipoamide dehydrogenase: The E3 subunit enzyme of mitochondrial α-ketoacid dehydrogenase complexes responsible for oxidising dihydrolipoamide back to lipoamide.

α-Ketoacid dehydrogenase complexes: Multi-enzyme assemblies that catalyse oxidative decarboxylation of key metabolic intermediates to their corresponding acyl-CoA products.

Flavin adenine dinucleotide (FAD): A redox-active cofactor that shuttles electrons within DLD and other dehydrogenases.

Reactive oxygen species (ROS): Highly reactive oxygen-derived molecules that can damage proteins, lipids and nucleic acids under pathological conditions.

RNA interference (RNAi): A genetic approach to reduce or silence expression of a target gene through sequence-specific degradation of its messenger RNA.

References

1. dldhcri3 zebrafish exhibited altered mitochondrial ultrastructure, morphology and dysfunction partially rescued by probucol or thiamine. JCI Insight (2024).
2. Structural and Biochemical Investigation of Selected Pathogenic Mutants of the Human Dihydrolipoamide Dehydrogenase. International Journal of Molecular Sciences (2023).
3. Dichloroacetate and thiamine improve survival and mitochondrial stress in a C. elegans model of dihydrolipoamide dehydrogenase deficiency. JCI Insight (2022).