Adult height in girls with Turner syndrome treated from before 6 years of age with a fixed per kilogram GH dose.

Objective: To evaluate adult height (AH) in 25 girls with Turner syndrome (TS) who were treated from before 6 years of age for 10.0 ± 1.7 years with a fixed GH dose of 0.33 mg/kg per week.
Patients and Design: After a 6-month pretreatment assessment all patients were measured 6-monthly under therapy to assess height SDS (H-SDS) and height velocity (HV) until AH achievement.
Results: Following initial acceleration, HV declined after the first 4 years of therapy. At the end of the sixth year of therapy, H-SDS gain was 1.9 ± 1.1. Thereafter, H-SDS gain from baseline decreased, becoming 0.9 ± 0.9 SDS at AH achievement. Bone maturation velocity did not significantly change throughout the prepubertal period. According to Lyon standards for TS, mean AH SDS was significantly higher than pretreatment H-SDS (P<0.0001), with a mean H-SDS change of 0.9 ± 0.9. However, the prevalence of patients with AH <-2 SDS (according to Sempé standards) was close to those recorded at the start of therapy (16/25 vs 18/25). No significant differences in terms of AH were found between patients with either X monosomy or X-chromosomal abnormalities and between girls with either spontaneous or induced puberty.
Conclusions: We infer that the therapeutic regimen adopted in this prospective study is sufficient to induce a significant growth acceleration during the first year, but the response waned after 6 years of treatment.