Basal serum neurokinin b levels in differentiating idiopathic central precocious puberty from premature thelarche

Objective: to find out the diagnostic role of kisspeptin and neurokinin b in idiopathic central precocious puberty (icpp) and premature thelarche (pt). methods: the girls who presented with early breast development before the age of 8 years were evaluated. patients with intracranial pathologies were excluded. basal and stimulated follicle-stimulating hormone/luteinizing hormone (lh) levels and basal neurokinin b/ kisspeptin levels were measured. patients who had peak value of lh >5 miu/ml and a bone age (ba)/chronological age (ca) ratio >1.1 were diagnosed as central precocious puberty (cpp),while cases who did not meet these criteria were diagnosed as pt. healthy age-matched prepubertal girls were included as the control group. results: the study group contained 25 girls with icpp (7±0.8 years),35 girls with pt (6.8±0.7 years),and 30 controls (6.7±0.7 years). basal serum kisspeptin and neurokinin b levels were 2.36±0.47 ng/ml and 2.61±0.32 ng/ml,respectively in the icpp group,2.23±0.43 ng/ml and 2.24±0.23 ng/ml,respectively in the pt group,and 1.92±0.33 ng/ml and 2.03±0.24 ng/ml,respectively in the controls. both kisspeptin and neurokinin b levels were higher in the icpp and pt groups compared to controls (p<0.05). moreover,basal neurokinin b level was different between icpp and pt groups (p<0.01). a serum neurokinin b level of 2.42 ng/ml provided the most appropriate level to differentiate icpp from pt,with a sensitivity of 84% and specificity of 77.1%. conclusion: differentiation of cpp from pt is sometime difficult,and there is a need for a simple method for the differential diagnosis. our results suggest that basal serum neurokinin b level can be used as an adjunctive parameter to differentiate iccp from pt. © 2017 by turkish pediatric endocrinology and diabetes society.