Analysis of Mitochondrial 4977-bp Deletion and D-Loop Variation in Iranian Non-Alcoholic Fatty Liver Disease Patients

Background: Accumulating evidence indicates that mitochondrial dysfunction is considered an effective factor in the formation or development of non-alcoholic fatty liver disease (NAFLD) although the underlying mechanisms of the changes are still unclear. Objectives: The aim of the study was to determine the 4977-bp deletion levels and variations in the displacement (D) loop region of mitochondrial DNA (mtDNA) in NAFLD patients. Methods: In this case-control study, 43 NAFLD patients and 156 controls were enrolled. The blood DNA of 43 patients with NAFLD and 156 healthy individuals was investigated to determine the 4977-bp deletion and sequence changes in the D-loop region using methods such as polymerase chain reaction (PCR), multiplex PCR, and DNA sequencing. Results: The results indicated that no 4977-bp deletion was found in any of the samples. 94 variations were found in the D-loop region including two deletions, four insertions, and 88 single nucleotide polymorphisms (SNP), 16 of which were just found in patients. There was a significant difference between the NAFLD patients and controls in six variants (P < 0.05). Two novel insertions (16171 ins T and 16221 ins C) were observed in patients. Finally, the results revealed no statistically significant difference (P > 0.05) in C variations in D310 mitochondrial DNA between the two groups. Conclusions: According to the findings, we believe that the disease damages the mitochondrial DNA and leads to the formation of these mutations. Our results also showed that D-loop alterations are frequent in NAFLD and may play a significant role in the progression of NAFLD.