en Nephrology Nephrology Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:14pt"><b><i><span style="color:blue">Background: </span></i></b>&beta;-thalassemia major is a hereditary disorder characterized by transfusion-dependent anemia and associated complications. In patients with &beta;-thalassemia major, one of the long-term complications of regular blood transfusion is renal dysfunction. This study aimed to evaluate serum &beta;2-microglobulin as a marker of the severity of renal tubular dysfunction and to examine the clinical factors associated with the severity of renal tubular dysfunction in children with &beta;-thalassemia major.</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Methods: </span></i></b>This cross-sectional analytical study was conducted on 134 non-diabetic children with &beta;-thalassemia major who attended thalassemia centers in Mazandaran Province, Iran. Data were collected using a structured checklist that included demographic information, laboratory findings, and clinical parameters. The severity of renal tubular dysfunction was assessed using serum &beta;2-microglobulin levels. Glomerular filtration rate was estimated using the revised Schwartz formula. Pearson correlation analysis was used for statistical analysis.</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Results: </span></i></b>A significant positive correlation was observed between &beta;2-microglobulin levels and age (r = 0.311, p < 0.001), number of blood transfusions per year (r = 0.390, p < 0.001), serum creatinine (r = 0.732, p < 0.001), blood urea nitrogen (r = 0.715, p < 0.001), and serum ferritin (r = 0.505, p < 0.001). In contrast, significant negative correlations were found with serum hemoglobin (r = &minus;0.433, p < 0.001) and creatinine clearance (r = &minus;0.383, p < 0.001).</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Conclusion: </span></i></b>Renal tubular dysfunction in children with &beta;-thalassemia major showed significant correlations with age, iron overload, anemia severity, and transfusion frequency. Serum &beta;2-microglobulin may serve as a useful marker for the early detection of tubular damage and may help guide preventive strategies in clinical practice.</span></span></span><br> &nbsp; Beta-thalassemia major, Pediatrics, Renal tubular dysfunction, β2-microglobulin, Iron overload, Biomarker 549 554 http://caspjim.com/browse.php?a_code=A-10-2467-2&slc_lang=en&sid=1 Roghayeh Akbari Roghayeh.akbari@yahoo.com 100319475328460057784 100319475328460057784 No Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Hassan Mahmoodi Nesheli mahmoodi86@yahoo.com 100319475328460057785 100319475328460057785 No Non-Communicable Pediatric Diseases Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, IR Iran Soha Salehi smmalekshah@gmail.com 100319475328460057786 100319475328460057786 No Student Research Committee, Babol University of Medical Sciences, Babol, Iran Mahmoud Hajiahmadi hajiahmadi@yahoo.com 100319475328460057787 100319475328460057787 No Clinical Research Development Unit of Amirkola Children's Hospital, Babol University of Medical Sciences, Babol, Iran Sahar Sadr Moharerpour drsaharsadr@gmail.com 100319475328460057788 100319475328460057788 Yes Non-Communicable Pediatric Diseases Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, IR Iran