SLC25A19 is a mitochondrial transporter that mediates thiamine pyrophosphate (TPP) uptake into mitochondria 1. The protein functions as a thiamine pyrophosphate transmembrane transporter and plays a critical role in mitochondrial metabolic homeostasis 2. SLC25A19 is required for mitochondrial respiration through regulation of NADH levels, complexes I and III enzymatic activity, and the tricarboxylic acid cycle 2. Biallelic SLC25A19 mutations cause two distinct disease phenotypes. Homozygous c.530G>C mutations cause Amish lethal microcephaly 3, while non-Amish mutations result in bilateral striatal necrosis with progressive axonal peripheral polyneuropathy 3. The non-Amish phenotype presents with fever-induced encephalopathy and Leigh-like features responsive to high-dose thiamine treatment (600 mg/day), which can prevent acute encephalopathic episodes and potentially prevent peripheral neuropathy if initiated early 3. Early treatment anticipation may prevent irreversible neurological damage 4. Beyond monogenic disease, SLC25A19 expression is elevated in hepatocellular carcinoma and colorectal cancer, where it predicts poor prognosis 567. SLC25A19 upregulation correlates with immune checkpoint gene expression and regulates p53 pathway signaling in cancer 57. These findings suggest SLC25A19 as both a therapeutic target and prognostic biomarker in malignancy.