Severe respiratory complex III defect prevents liver adaptation to prolonged fasting

Abstract : Background and aims: Next generation sequencing approaches have tremendously improved the diagnosis of rare genetic diseases. It may however be faced with difficult clinical interpretation of variants. Inherited enzymatic diseases provide an invaluable possibility to evaluate the function of the defective enzyme in human cell biology. This is the case for respiratory complex III, which has 11 structural subunits and requires several assembly factors. An important role of complex III in liver function is suggested by its frequent impairment in human cases of genetic complex III defects. Methods: We report the case of a child with complex III defect and acute liver dysfunction with lactic acidosis, hypoglycemia, and hyperammonemia. Mitochondrial activities were assessed in liver and fibroblasts using spectrophotometric assays. Genetic analysis was done by exome followed by Sanger sequencing. Functional complementation of defective fibroblasts was performed using lentiviral transduction followed by enzymatic analyses and expression assays. Results: Homozygous, truncating, mutations in LYRM7 and MTO1, two genes encoding essential mitochondrial proteins were found. Functional complementation of the complex III defect in fibroblasts demonstrated the causal role of LYRM7 mutations. Comparison of the patient’s clinical history to previously reported patients with complex III defect due to nuclear DNA mutations, some actually followed by us, showed striking similarities allowing us to propose common pathophysiology. Conclusions: Profound complex III defect in liver does not induce actual liver failure but impedes liver adaptation to prolonged fasting leading to severe lactic acidosis, hypoglycemia, and hyperammonemia, potentially leading to irreversible brain damage.
Type de document :
Article dans une revue
Journal of Hepatology, Elsevier, 2016, 65 (2), pp.377-85. 〈10.1016/j.jhep.2016.04.017〉
Liste complète des métadonnées

Littérature citée [31 références]  Voir  Masquer  Télécharger

http://www.hal.inserm.fr/inserm-01321215
Contributeur : Anne Lombès <>
Soumis le : mercredi 25 mai 2016 - 11:06:24
Dernière modification le : lundi 17 septembre 2018 - 11:14:08
Document(s) archivé(s) le : vendredi 26 août 2016 - 10:27:50

Fichier

Manuscript for HAL.pdf
Fichiers produits par l'(les) auteur(s)

Identifiants

Collections

Citation

Laura Kremer, Caroline L 'Hermitte-Stead, Pierre Lesimple, Mylène Gilleron, Sandrine Filaut, et al.. Severe respiratory complex III defect prevents liver adaptation to prolonged fasting. Journal of Hepatology, Elsevier, 2016, 65 (2), pp.377-85. 〈10.1016/j.jhep.2016.04.017〉. 〈inserm-01321215〉

Partager

Métriques

Consultations de la notice

374

Téléchargements de fichiers

264