LYRM7 encodes a mitochondrial assembly factor essential for respiratory chain complex III (cytochrome bc1 complex) biogenesis. The protein functions as a chaperone in the mitochondrial matrix, specifically binding to and stabilizing the Rieske iron-sulfur protein (UQCRFS1) prior to its incorporation into the complex III dimer 1. LYRM7 is critical for proper complex III holocomplex assembly, as demonstrated by functional complementation studies showing that LYRM7 mutations directly cause complex III deficiency 2. Pathogenic mutations in LYRM7 result in mitochondrial complex III deficiency, nuclear type 8, characterized by a distinctive neuroimaging pattern of multifocal cavitating leukoencephalopathy with periventricular white matter lesions 13. Clinical manifestations include recurrent metabolic acidosis, encephalopathy, developmental delays, and episodic neurological deterioration often triggered by febrile illnesses 13. The protein appears to have broader biological significance beyond its assembly function, as LYRM7 expression is regulated by TNF-α-induced NF-κB signaling and influences mitochondrial supercomplex assembly, with reduced levels associated with increased cancer cell invasiveness 4. LYRM7 levels also correlate with exercise adaptation and metabolic responses in skeletal muscle 5.