GDF2 and hypertensive disorder: This was a cross-sectional study with a single center on Chinese patients, it can’t determine a cause-effect relationship between circulating BMP9 and HTN as well as CHD; 2) Our study did not examine the sources of BMP9; 3) The size of the sample is relatively small considering that it is divided into four study groups, one independent from the other, and each with a different number of patients.