FSH, LH, inhibin B and estradiol levels in Turner syndrome depend on age and karyotype: longitudinal study of 70 Turner girls with or without spontaneous puberty.

BACKGROUND Ovarian function in Turner syndrome (TS) patients depends on the specific karyotype. This retrospective clinical study evaluates the pituitary-gonadal axis during infancy, childhood and adolescence in TS patients according to karyotype and ovarian function. METHODS A cohort of 70 TS patients (0-16 years) followed at a tertiary referral centre for paediatric endocrinology were included. Longitudinal measurements of reproductive hormones (FSH, LH, inhibin B and estradiol) prior to hormonal replacement treatment in 66 patients related to karyotype (A, 45,X; or B, miscellaneous karyotypes) and ovarian function (spontaneous puberty or absent spontaneous puberty) were compared with an age-matched reference range of 2406 healthy Danish females. RESULTS The prevalence of spontaneous puberty was 6% for 45,X and 54% for miscellaneous karyotypes, P = 0.001. In all TS patients, gonadotrophins were higher during infancy and at expected puberty compared with levels at mid-childhood, where 21/25 and 23/27 had FSH and LH levels, respectively, within the reference range. In patients with absent spontaneous puberty, 10/12 had FSH in the reference range during the mid-childhood nadir. 45,X-TS patients had undetectable inhibin B at 0-16 years. Ovarian failure was predicted in 20/20 patients with exclusively undetectable inhibin B, while 9/10 with detectable inhibin B entered puberty spontaneously. Estradiol levels were elevated from 4 to 8 years. CONCLUSIONS Ovarian function in TS patients is associated with the specific karyotype, and multiple undetectable inhibin B values during mid-childhood may predict absence of spontaneous puberty, although the specificity of the test is low. The biphasic age pattern of gonadotrophins was preserved in all patients, and spontaneous gonadotrophins are not useful as a diagnostic marker for TS in girls aged 6-10 years.