Karyotype Abnormalities in the X Chromosome Predict Response to the Growth Hormone Therapy in Turner Syndrome

Short stature is characteristic for Turner syndrome (TS) patients, and particular karyotype abnormalities of the X chromosome may be associated with different responsiveness to recombinant human GH (rhGH) therapy. The aim of the study was to analyze the effect of different types of TS karyotype abnormalities on the response to rhGH therapy. A total of 57 prepubertal patients with TS treated with rhGH with a 3 year follow-up were enrolled in the study and categorized according to their karyotype as X monosomy (n = 35), isochromosome (n = 11), marker chromosome (n = 5), or X-mosaicism (n = 6). Height and height velocity (HV) were evaluated annually. In the first year, all groups responded well to the therapy. In the second year, HV deteriorated significantly in X-monosomy and isochromosome in comparison to the remaining two groups (p = 0.0007). After 3 years of therapy, all patients improved the score in comparison to their target height, but better outcomes were achieved in patients with marker chromosome and X-mosaicism (p = 0.0072). X-monosomy or isochromosome determined a poorer response during the second and third year of rhGH therapy. The results of the study indicate that the effects of rhGH therapy in patients with TS may depend on the type of TS karyotype causing the syndrome.