Defective TBXAS1 causes GHDD

Thromboxane-A synthase (TBXAS1), an enzyme of the arachidonic acid cascade, produces thromboxane A2 (TXA2) from prostaglandin H2 (PGH2). Together with prostacyclin (PGI2), TXA2 plays a key role in the maintenance of haemostasis. It is also a constrictor of vascular and respiratory smooth muscle and implicated in the induction of osteoclast differentiation and activation. Defects in TBXAS1 can cause Ghosal hematodiaphyseal dysplasia (GHDD; MIM:231095), a rare autosomal recessive disorder characterised by increased bone density with predominant diaphyseal involvement and aregenerative anemia, a bone marrow failure where functional marrow cells are regenerated slowly or not at all.

Summary from Reactome (R-HSA-5579032), read 2026-09-23.