MRPL44 is a structural component of the 39S large subunit of the mitochondrial ribosome 1 that plays a critical role in regulating oxidative phosphorylation (OXPHOS) capacity. The protein localizes to the mitochondrial matrix and can form multimers, functioning in the assembly and stability of nascent mitochondrial polypeptides as they exit the ribosome 2. MRPL44 regulates expression of mitochondrial DNA-encoded genes at both RNA and protein translation levels, ultimately impacting ATP synthesis and respiratory capacity 2. Pathogenic MRPL44 variants cause combined oxidative phosphorylation deficiency, manifesting primarily as childhood-onset hypertrophic cardiomyopathy with a progressive multisystem phenotype 3. Affected individuals present with cardiac dysfunction in infancy, lactic acidosis, and additional complications including pigmentary retinopathy, neurological symptoms, and renal insufficiency 34. Disease mechanisms involve reduced mitochondrial protein synthesis causing complex I and IV assembly defects 4. Remarkably, MRPL44 knockout embryos fail to initiate gastrulation despite normal implantation, exhibiting severely compromised ATP production and mitochondrial dysfunction 5, indicating MRPL44 is essential for early mammalian development. Additionally, MRPL44 expression serves as a metabolic marker correlating with lymph node metastasis risk in papillary thyroid carcinoma 6.