Succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial

SDHA (succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial) is the flavoprotein component of complex II of the mitochondrial electron transport chain (UniProt: P31040). It catalyzes electron transfer from succinate to ubiquinone (coenzyme Q) and participates in malate oxidation, functioning both in cellular respiration and as a potential tumor suppressor.

SDHA is widely expressed in metabolically active tissues and has established roles in mitochondrial function. Pathogenic variants cause severe mitochondrial disorders including complex II deficiency, Leigh syndrome, dilated cardiomyopathy, pheochromocytoma/paraganglioma syndrome, and neurodegeneration with ataxia and optic atrophy (UniProt: P31040).

SDHA is curated as disease-relevant in Alzheimer's Disease (Chaparral AD proteomics). However, its direction of change in AD brain is ambiguous: quantitative proteomics data from post-mortem AD tissue versus age-matched controls showed a mean log2 fold-change of 0.0347 across multiple subcellular fractions, indicating negligible net change overall (Chaparral AD proteomics). The minimal effect size suggests SDHA is not substantially dysregulated in AD pathology at the protein level.