ESPE Abstracts

Introduction: Growth hormone (GH) treatment is used to accelerate growth in patients with Turner syndrome (TS). During treatment, evaluation of IGF-1 is strongly recommended for efficacy and safety. Some patients, despite optimum GH doses, have persistent high IGF-1 levels. In this study, we aimed to evaluate the relationship between IGF-1 levels, IGF1R and growth responses of TS patients on GH treatment.

Method: 54 patients with TS (19 classic, 35 mosaic) using GH (45μg/kg/day) were evaluated retrospectively. At the onset, SDS of birth weight (BW), anthropometric measurements, target height, and bone age (BA); and at the first and fourth years of GH-treatment, SDS of anthropometric measurements and IGF-1; and growth velocity (GV) and BA of the patients were noted. According to IGF-1 levels, the patients were divided into 5 groups: patients with IGF-1-SDS in normal ranges on GH treatment constituted Group1; patients whose IGF-1 SDS were increased on treatment and returned to normal with 10-20% dose reduction formed Group2; patients whose IGF-1SDS remained high despite 10-20% dose reduction formed Group3; patients whose IGF-1 SDS returned to normal without any dose change formed Group4; and patients whose IGF-1 SDS remained high without any dose change formed Group5. Comparisons were made between groups covering patients on treatment with normal IGF-1 levels (Group1), and with increased IGF-1 levels (Groups 2,3,4 and 5). IGF-1R gene analysis was performed in cases where IGF-1 levels were increased at least once.

Results: The age of treatment onset was slightly higher in Group1 compared to others (P = 0.046). No statistical significance was observed in comparison of BW, height-SDS, BA and IGF-1SDS at the onset of treatment between Group1 and Groups 2,3,4,5. While the weight and BMI-SDS were significantly higher in Groups 2-3-4-5 (P = 0.03; P = 0.04), GV was better in Group 1 (P = 0.025). At 1st-year of treatment, weight-SDS (P = 0.001), BMI-SDS (P = 0.002); and at 4^th year of treatment, weight-SDS (P = 0.002), and BMI-SDS (P = 0.002) were higher in Groups 2-3-4-5. GV in 1st-year (P = 0.037) and 4th-year (P = 0.038) were better in Groups2-3-4-5. No pathogenic variants in IGF-1R gene were detected in any of the patients.

Conclusion: The weight and BMI-SDS of patients whose IGF-1-levels were increased at least once were higher than of those patients with normal IGF-1 levels on GH-treatment. Moreover, GV was higher in patients with high IGF-1SDS than in patients with normal IGF-1SDS, albeit GH dose decrease in this group. High IGF-1 levels in these patients could not be explained by IGF-1R gene mutation.