Background: Precocious puberty, pubertal development in girls before 8 years, has considerable biological, psychosocial, and long-term health implications. It is classically ascribed to the premature activation of the hypothalamic-pituitarygonadal axis, and hence an LH response >5 U/l in the LHRH test. Whilst this group of patients is well understood, there is a paucity of literature characterising patients who show pubertal development not driven by LH, atypical precocious puberty. It has been hypothesised that obesity and endocrine disruptors may play a role.
Objective and hypotheses: i) To identify the number of girls in our unit with signs of early puberty and a non-LH predominant (LH <5 U/l) response in the LHRH test and ii) to compare their clinical characteristics to those with an LH predominant (LH >5 U/l) response in the LHRH test.
Method: 148 girls had an LHRH test between 2004 and 2014. Tanner staging, symptoms and signs of puberty, LHRH test results, bone age, height, weight and BMI were collected retrospectively. Patients with an organic cause for precocious puberty and premature thelarche (B2-5, and P1 or bone age advancement <1 year) were excluded.
Results: We identified 19 patients with an LH predominant response and 20 patients with a non-LH predominant response. Age at first symptom (breast or pubic hair development) and age at evaluation were not significantly different. Also, there was no significant difference in Tanner staging at presentation, bone age advancement or height SDS between the groups. However, the non-LH predominant group had significantly higher weight SDS (P=0.025) and BMISDS (P=0.019).
Conclusion: Girls with atypical precocious puberty have similar levels of pubertal development and bone age advancement as their peers with classical precocious puberty. Their increased BMI supports the hypothesis that obesity may result in precocious puberty due to reduced SHBG and increased aromatase activity leading to increased oestrogen bioavailability.
01 Oct 2015 - 03 Oct 2015