The correlation of the IGF-I, IGFBP-3, and ALS generation test to height velocity after 6 months of recombinant growth hormone therapy in girls with Turner syndrome.

BACKGROUND/AIMS: Girls with Turner syndrome (TS) have short stature and benefit from growth hormone therapy (hGH). Some TS present a significant change in height velocity in response to hGH while others have only a mild increment. Our objective was to correlate the response to hGH (height velocity after 6 months of therapy) to biochemical data prior to and after the beginning of hGH to try to define a tool to predict the response to hGH. METHODS: Thirteen TS participated in the study (ages 3.5-14 years). Levels of IGF-I and IGFBP-3 were measured before and 5, 30 and 90 days after starting hGH (0.05 mg/kg/day), ALS levels were measured only prior and after 5 days. RESULTS: The mean height velocity (+/-SD) increased from 4.27 (+/-1.18) cm/year to 8.46 (+/-2.17) cm/year (p=0.0001). There was no correlation between the height velocity encountered and the expected height velocity using published mathematical models. Basal ALS values correlated to height velocity SDS and IGF-I and IGFBP-3, after 90 days, correlated to height velocity. Most of the data was too scattered to be used individually for each patient. CONCLUSIONS: Even though we observed a relationship between biochemical markers and height velocity in TS treated with hGH, the response to hGH therapy in this condition is highly variable.