en بيولوژي Biology review review <div style="text-align: justify;"><strong>Background:</strong> Methylmalonic acidemia (MMA) is a rare autosomal recessive metabolic disorder resulting from a genetic defect in methylmalonyl-CoA mutase (MCM) or a defect in the biosynthesis of its cofactor, adenosyl-cobalamin (AdoCbl). The disease is caused by a mutation in six main genes (MUT, MMAA, MMAB, MMADHC, MMACHC, and MCEE). In this investigation, we estimate MMAdisease gene frequencies globally and report MMA-causative mutations in the Iranian population.<br> <strong>Methods:</strong> Human gene mutation database (HGMD) has been utilized to estimate MMA-disease gene frequencies. To compile MMA mutations in Iran, we systematically reviewed PubMed, Google Scholar, CIVILICA, Magiran, and SID databases to explore relevant articles in English and Persian.<br> <strong>Results: </strong>The frequencies of causative genes among MMA patients at the global level were as follows: MUT (64.14%), MMACHC (17.74%), MMAA (13.48%), MMAB (7.1%), MMADHC (2.9%), and MCEE (0.85%). Until February 11, 2024, 24 MMA mutations had been compiled from the Iranian population; of which 11 mutations (45.8%) had been diagnosed only in Iran and had not been addressed in other populations yet.<br> <strong>Conclusion: </strong>Collection and recognition of MMA mutations in the Iranian population can be helpful for early diagnosis and treatment before the onset of neurological manifestations in neonates.</div> &nbsp; methylmalonic academia, mutation, Iranian population, methylmalonyl-CoA mutase 37 48 http://rmm.mazums.ac.ir/browse.php?a_code=A-10-850-1&slc_lang=en&sid=1 Ghazaleh Malekizadeh ghazalehmalekizadeh@gmail.com 100319475328460011891 0009-0009-3150-4782 No Department of Molecular and Cell Biology, Faculty of Science, University of Mazandaran, Babolsar, Iran Omid Jazayeri ojazayeri@gmail.com 100319475328460011892 100319475328460011892 Yes Department of Molecular and Cell Biology, Faculty of Science, University of Mazandaran, Babolsar, Iran Morteza Alijanpour m.alijanpour@yahoo.com 100319475328460011893 100319475328460011893 No Non-communicable pediatric Disease Research Center, Health Research Institute, Babol University of Medical Science, Babol, Iran Majid Tafrihi m.tafrihi@umz.ac.ir 100319475328460011894 100319475328460011894 No Department of Molecular and Cell Biology, Faculty of Science, University of Mazandaran, Babolsar, Iran