Objective:To measure components of the circulating transforming growth factor β (TGFβ)system in patients with Turner syndrome (TS) compared to relevant controls and to ascertain correlation with endocrine and cardiovascular parameters.Methods:TGFβ1,TGFβ2 and endoglin (a vascular TGF receptor component) were measured using enzyme-linked immunoassays in the sera of 40 subjects with TS and 40 healthy volunteer women.The cardiovascular phenotype in TS subjects was extensively characterized by cardiac magnetic resonance (MR) and echo.Results:TGFβ1 levels were about 3-fold higher in TS while TGFβ2 levels were about 3.5-fold higher in controls (P ＜0.000 1 for both).Soluble endoglin levels were 25％ higher in TS (P ＜0.000 1 ).Variation in TGFβ system components was not explained by age,blood pressure,platelet count,thyroid function,body proportions or cardiovascular phenotype.Conclusion:There is profound perturbation of the TGFβ system evident in the circulation of individuals with TS.