A patient-based Drosophila model for mitochondrial S-Adenosylhomocysteine transport deficiency

ABSTRACT: The SLC25A26 gene encodes a mitochondrial inner membrane carrier that transports S-adenosylmethionine (SAM) into the mitochondrial matrix in exchange for S-adenosylhomocysteine (SAH). SAM is the predominant methyl-group donor for most cellular methylation processes, of which SAH is produced as a by-product. Pathogenic, bi-allelic SLC25A26 variants are a recognized cause of mitochondrial disease in children, with a severe neonatal-onset caused by decreased SAM transport activity. We describe two, unrelated adult cases presenting with exercise intolerance and mitochondrial myopathy associated with bi-allelic variants in SLC25A26 which lead to marked respiratory chain deficiencies and mitochondrial histopathological abnormalities in skeletal muscle that are comparable to the early-onset cases. We demonstrate using both mouse and fruit fly models that impairment of SAH, rather than SAM, transport across the mitochondrial membrane is the cause of this milder, later onset clinical phenotype. In this submission, the total larval proteome was assessed at two, three and four days after egg laying in mutants expressing a SAMC.R166Q mutation versus wDah genetic background controls. Our finding of a novel pathomechanism associated with a known disease-causing protein highlights the potential of precision medicine in clinical decision making.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Drosophila Melanogaster (fruit Fly)

DISEASE(S): Mitochondrial Metabolism Disease

SUBMITTER: Florian Schober  

LAB HEAD: Anna Wredenberg

PROVIDER: PXD026900 | Pride | 2022-01-19

REPOSITORIES: Pride