Prediction of Pubertal Growth at Start of Estrogen Replacement Therapy in Turner Syndrome

In estrogen replacement therapy in Turner syndrome, there is no report which recommends the timing of the start of estrogen therapy in relation to height or adult height prediction. We have established a prediction model for pubertal growth (height difference from the start of estrogen therapy until adult height) at the start of estrogen replacement therapy. Twenty-seven Turner girls without spontaneous puberty were divided into two groups according to birth years; Group I consisted of 16 patients born from 1980-1989 and Group II consisted of 11 patients born before 1980. Using clinical characteristics from Group I, stepwise multiple regression analysis taking pubertal growth as an independent factor, and chronological age, bone age (TW2 RUS method standardized for Japanese children), height and height SDS as dependent factors revealed following formula (p<0.001, R2=0.737): (pubertal growth) = - 1.01x (Chronological age at start of E) - 0.326x (height at start of E) - 1.779x (bone age at start of E) + 90.997. Predicted adult height was obtained by adding predicted pubertal growth to height at the start of estrogen therapy. The mean absolute difference between real adult height (tallest height after height velocity less than 1 cm/yr) and predicted adult height was 1.6 ± 0.9 cm (0.3-2.8 cm) in Group I. When this prediction model was applied to Group II, The mean absolute difference between real adult height and predicted adult height was 1.0 ± 0.7 cm (0.1-2.0 cm). A prediction model for pubertal growth at start of estrogen therapy in Turner syndrome was obtained. Using this prediction model, the timing of the start of estrogen therapy can be decided in consideration of the patient's desired adult height.