Abstract: The invention relates to methods and compositions for promoting bone growth, bone healing and/or bone formation. Disclosed herein are isolated truncated Wilms tumor on gene chromosome X (WTX) polypeptides and uses thereof. Also disclosed are methods of treating a bone related disease or condition in a subject by modulating the expression or activity of a (WTX) polypeptide in bone cells of the subject. The bone related disease or condition is any disease or condition including bone related trauma or injury due to any cause including surgery. The compositions and methods according to the invention are useful for enhancing and stimulating bone mineralization and for preferentially directing the differentiation of certain stem cells, thereby altering cell fate.