The role of kisspeptin and MKRN3 in the diagnosis of central precocious puberty in girls

Objective: To evaluate the characteristics and significance of serum kissp eptin and makorin ring finger protein 3 (MKRN3) levels for the diagnosis o f central precocious puberty (CPP) in girls. Method: Thirty four individuals with CPP, 17 individuals with prematur e thelarche (PT), and 28 age-matched prepubertal girls as normal control (NC) wer e recruited in this case-control study. Physical measurements included BMI and test s for breast, bone, and sexual characteristics. Biochemical measurements included serum LH, FSH, estradiol, insulin-like growth factor-1, MKRN3, and kisspeptin. Blood samp les were taken from individuals with CPP and PT before the gonadotrophin-releasing hormone stimulation test and at 30, 60, 90, and 120 min after injection with tripto relin. Results: Serum kisspeptin levels were higher in the CPP group when comp ared to the NC group (P = 0.020), while serum MKRN3 levels were lower in the two groups (P = 0.028). There were no significant differences between the CPP and PT grou ps as well as the PT and NC groups (all, P > 0.05). The cut-off value of serum kisspeptin differentiating patients with CPP from those without CPP was 0.40 nmol/L, with 82.4% sensitivity and 57.1% specificity, while the cut-off value of serum MKRN3 was 0.3 3 pmol/L, with 79.4% sensitivity and 53.6% specificity. The area under the curves (AU Cs) of both kisspeptin and MKRN3 for differentiating those girls with CPP from PT were less than 0.5. Conclusions: Serum levels of kisspeptin and MKRN3 may play an auxiliary rol e in predicting CPP. However, the two measurements were not able to differentiat e girls with CPP from PT and prepubertal control. This study emphasizes the need to sear ch for markers to simplify the accurate diagnosis of CPP in girls.