Abnormal accumulation of glutamate tRNA fragments (tRF-Glu) in Alzheimer's disease (AD) patients' brains competitively binds mitochondrial leucine synthetase (LaRs2, a mitochondrial aminoacyl-tRNA synthetase involved in mitochondrial protein translation), disrupting leucine tRNA synthetization and mitochondrial protein translation. The gene discussed is LARS2; the disease is Alzheimer disease.