Prediction of final height in Turner's syndrome. A comparative study.

Various methods are used for prediction of final height in girls with Turner's syndrome (TS), but their accuracy has not been systematically investigated or compared. We have compared predictions of final height made with the most commonly used methods in 20 Turner girls at ages 9.5-18 years. Growth standards based on growth and final height of 78 Danish Turner women were used for calculation of standard deviation scores (SDS). In order to provide the necessary basis for "index of potential height" (IPH) method, bone age development was determined from 74 X-rays of 38 untreated Turner girls aged 5.2-19 years. This method was further modified and improved for use in TS. Prediction methods based only on height and chronological age (CA) showed little difference from methods including bone age. The IPH method in our modification was more accurate than those of Bayley-Pinneau and Tanner. At younger ages the IPH method showed better results when using Tanner-Whitehouse 2 (TW2) bone age than when using Greulich-Pyle bone age. Accuracy of predictions were considerably improved by combining methods with and without allowance for bone age. Combinations including the IPH method based on TW2 bone age appeared to be the most accurate. Predictions of final height in Turner's syndrome should therefore be made by combining the IPH method and one of the methods based on height and CA.