Significance of serum neurokinin B and kisspeptin levels in the differential diagnosis of premature thelarche and idiopathic central precocious puberty.

The aim of the present study was to investigate the diagnostic role of serum neurokinin B level and its relationship with kisspeptin and leptin, which are known to be involved in the initiation of pubertal process. Girls who presented with breast development (<8 years) were included in the study. All patients underwent bone age assessment. Basal levels of serum follicle stimulating hormone and luteinizing hormone were measured and gonadotropin releasing hormone stimulation test was performed. Patients with a bone age/chronological age ratio >1 and a peak luteinizing hormone response in gonadotropin releasing hormone stimulation test >5mIU/L were included in the central precocious puberty group, while patients who did not meet these criteria were included in the premature thelarche group. Patients with organic pathologies were excluded. Healthy prepubertal girls with similar age were included as the control group. Leptin, kisspeptin and neurokinin B levels were measured by ELISA method. The study included 20 girls with idiopathic central precocious puberty 22 girls with premature thelarche and 24 prepubertal controls. While serum kisspeptin, leptin and neurokinin B levels were significantly higher in central precocious puberty and premature thelarche groups compared to controls, no significant difference was found between central precocious puberty and premature thelarche groups. Increased serum levels of leptin, kisspeptin and neurokinin B in patients with premature thelarche and central precocious puberty suggest that they take part during the initiation of pubertal process, however, these markers are not able to differentiate patients with central precocious puberty from premature thelarche.