Endocrine Abstracts

Introduction: Turner syndrome (TS) is a condition caused by structural or numerical abnormalities of X chromosome. Growth deficiency is characteristic for patients with TS, and particular karyotype abnormalities of the X chromosome may be associated with different responsiveness to human GH (hGH) therapy. The aim of the study was to determine the effect of TS karyotype on growth velocity during hGH therapy in TS.

Methods: 23 TS patients treated with hGH with at least 2 years follow-up, were enrolled in a longitudinal observational study. Genetic analyses in order to evaluate the X chromosome structural or numerical abnormalities were performed and patients were categorized as X-monosomy (n=12), X-mosaicism with structural abnormalities of the second X (n=6), X-mosaicism without structural abnormalities of the second X (n=4) and structural abnormalities of the second X (n=1). Anthropometric parameters and height velocity (HV) were evaluated annually. Height and HV were expressed as SDS.

Results: In our study the lowest mean HVSDS in the first year of hGH therapy in TS with X-monosomy in comparison to patients with other chromosome abnormalities (+1.83±2.39 vs +4.4±2.59; P<0.002) was showed. In the second year of therapy the tendency of a lower mean HVSDS in patients with X-monosomy was noted, though without a statistical significance (P=0.243). No statistical difference in HVSDS in the first and second year of hGH therapy between patients with X-mosaicism with structural abnormalities of the second X, X-mosaicism without structural abnormalities of the second X and structural abnormalities of the second X were recorded.

Conclusions: X-monosomy determines a poorer growth response during the first year of hGH therapy in TS. The best response to hGH therapy during the first year was observed in TS patients with X-mosaicism with structural abnormalities of the second X.