<unk>  is an inherited autosomal recessive disorder due to a mutation in both copies of the TBXAS1 gene on chromosome 7q34. The TBXAS1 gene codes for the enzyme Thromboxane-A synthase. When known patients with the disease were sequenced for the TBXAS1 gene they had a homozygous missense mutation. The TBXAS1 gene mainly transcribes in cells involved with the skeletal system and muscular system. The increased bone density is due to lopsidedness between bones forming and bone resorption. This enzyme has a couple of essential functions in the body that, if removed, could lead to the symptoms observed with the disease. Thromboxane-A synthase is responsible for platelet aggregation and the regulation of bone mineral density. Thromboxane-A synthase regulates bone mineral density by influencing the two genes TNFSF₁₁ and TNFSF₁₁B, which encode for RANKL and osteoclastogenesis inhibitory factor in osteoblasts, so if the regulation did not occur it consequently leads to sclerosis. Even though Thromboxane-A synthase is important for platelet aggregation it is important to note that patients with this disease do not suffer from any bleeding problems. The refractory anemia also called corticosteroid sensitive anemia, is likely due to fibrotic scarring or sclerosis, which is the stiffening of the tissue when organ-specific tissue is replaced with connective tissue. Thromboxane-A synthase also participants in the arachidonic acid metabolism pathway, which has effects on the prostaglandin E2 levels. A decrease in Thromboxane-A synthase leads to an increase in prostaglandin E2 levels which may affect erythroid precursor cells by suppressing them which likely leads to refractory anemia. There are still unanswered questions about the effect of a compromised TBXAS1 gene function and its affect in<unk> .
Ghosal hematodiaphyseal dysplasia
Pseudo-Hurler polydystrophy
Craniodiaphyseal dysplasia
Sirenomelia
Achondrogenesis type 2
Mesomelia
Acrofrontofacionasal dysostosis
Thanatophoric dysplasia