GTPBP6 is a GTP-binding protein located in the pseudoautosomal region of the sex chrX|Y with dual roles in mitochondrial function. The protein facilitates both assembly and recycling of mitochondrial ribosomes, functioning analogously to the bacterial ribosome-recycling factor HflX 1. During ribosome biogenesis, GTPBP6 promotes maturation of the peptidyl transferase center by triggering progression through assembly intermediates 2, while also enabling dissociation of ribosomes post-translation 3. The gene escapes X inactivation and is expressed across multiple tissues. In Klinefelter syndrome (47,XXY), GTPBP6 overexpression shows inverse correlation with verbal IQ and other measures of verbal cognition 4, suggesting a role in neurodevelopment. Notably, GTPBP6 is one of fourteen X chrX|Y genes showing tissue-specific dysregulation across blood, fat, and muscle in individuals with sex chromosome X|Y 5. The gene has been identified as recurrently mutated in pancreatic ductal adenocarcinoma metastases, though its functional contribution to cancer progression remains unclear. Defects in mitochondrial translation factors like GTPBP6 are associated with oxidative phosphorylation deficiency and severe human disease.