Forny P Hochuli M Rahman Y Deheragoda M Weber A Baruteau J Grunewald S 2019 Methylmalonic aciduria (MMA) is an inherited metabolic disease caused by methylmalonyl-CoA mutase deficiency. Early-onset disease usually presents with a neonatal acute metabolic acidosis, rapidly causing lethargy, coma, and death if untreated. Late-onset patients have a better prognosis but develop common long-term complications, including neurological deterioration, chronic kidney disease, pancreatitis, optic neuropathy, and chronic liver disease. Of note, oncogenesis has been reported anecdotally in organic acidurias. Here, we present three novel and two previously published cases of MMA patients who developed malignant liver neoplasms. All five patients were affected by a severe, early-onset form of isolated MMA (4 mut0 , 1 cblB subtype). Different types of liver neoplasms, that is, hepatoblastoma and hepatocellular carcinoma, were diagnosed at ages ranging from infancy to adulthood. We discuss pathophysiological hypotheses involved in MMA-related oncogenesis such as mitochondrial dysfunction, impairment of tricarboxylic acid cycle, oxidative stress, and effects of oncometabolites. Based on the intriguing occurrence of liver abnormalities, including neoplasms, we recommend close biochemical and imaging monitoring of liver disease in routine follow-up of MMA patients. application/pdf https://sonar.ch/global/documents/38196 eng info:eu-repo/semantics/altIdentifier/doi/10.1002/jimd.12143 info:eu-repo/semantics/altIdentifier/pmid/31260114 info:eu-repo/semantics/openAccess Journal of inherited metabolic disease. - 2019 hepatoblastoma hepatocellular carcinoma liver methylmalonic aciduria mitochondrial dysfunction oncogenesis oxidative stress Acidosis, Lactic Adult Age of Onset Amino Acid Metabolism, Inborn Errors Brain Diseases, Metabolic, Inborn Child Female Humans Infant Infant, Newborn Liver Liver Neoplasms Male Metabolism, Inborn Errors Methylmalonyl-CoA Mutase Tomography, X-Ray Computed Ultrasonography Young Adult Liver neoplasms in methylmalonic aciduria: An emerging complication. http://purl.org/coar/resource_type/c_6501