This study aims to investigate the possible role of circulating microRNA-142-3p (miR-142-3p) in the
development of graves disease (GD) and its association with the antibody directed against thyroid
stimulating hormone receptor (TSHR-Ab) production in patients with GD. Forty patients with positive
TSHR-Ab enrolled in this study were divided ,based on treatment, into (22 untreated (newly diagnosed) and
18 treated patients) and based on family history (30 with positive family history and 10 with negative family
history). In addition to forty healthy subjects with sex and age matching as a control group. The expression
level of circulating miR-142-3p was determined by two steps reverse transcription polymerase chain reaction
(RT-PCR) technique. Results show that there is a significant elevation (p < 0.01) in the expression of miR-
142-3p in the serum of both treated and untreated patients compared with controls and in patients with
positive family history compared with negative family history. While its expression is non-significantly
lower (P > 0.05) in the serum of treated patients compared with untreated ones. It has been found that miR-
142-3p expression was positively correlated with levels of TSHR-Ab, FT3, and FT4. In addition, the miR-
142-3p expression has a good diagnostic accuracy with sensitivity (82%) and specificity (80%). In
conclusion, the differential expression of miR-142-3p between patients and healthy controls appears as a
potential biomarker for diagnosis of GD and the positive correlation of miR-142-3p with TSHR-Ab
suggesting the contribution of this miRNA in the development of GD.