Defective TBXAS1 does not isomerise PGH2 to TXA2

Stable Identifier
Reaction [transition]
Homo sapiens
Locations in the PathwayBrowser
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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. Mutations that can cause GHDD are L488P, L83P, G482W and R413E (Genevieve et al. 2008).

Literature References
PubMed ID Title Journal Year
18264100 Thromboxane synthase mutations in an increased bone density disorder (Ghosal syndrome)

Munnich, A, Isidor, B, Serre, V, Bellais, S, Dreyfus, M, de Vernejoul, MC, Bader-Meunier, B, Vignon-Savoye, C, Le Merrer, M, Gaussem, P, Fischer, AM, Blanche, S, Picard, C, Djouadi, F, Proulle, V, Legeai-Mallet, L, Cormier-Daire, V, Geneviève, D

Nat. Genet. 2008
Catalyst Activity

thromboxane-A synthase activity of TBXAS1 mutants [endoplasmic reticulum membrane]

Normal reaction
Functional status

Loss of function of TBXAS1 mutants [endoplasmic reticulum membrane]

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