TBXAS1 and anemia (phenotype): Ghosal hematodiaphyseal dysplasia (OMIM #231095), an autosomal recessive disorder due to loss-of-function mutations in the TBXAS1 gene encoding thromboxane synthase,(78) causes refractory anemia and skeletal dysplasia affecting diaphyses and metaphyses even more extensively than in CED.(79) Thromboxane synthase produces thromboxane A2 and thereby modulates expression of RANKL (increases) and OPG (decreases).(78) We did not measure serum RANKL or OPG levels in our patients.