Ghosal hematodiaphyseal dysplasia

A skeletal dysplasia caused by a variant in the TBXAS1 gene, characterized by increased bone density with diaphyseal dysplasia, pancytopenia or single‑lineage cytopenias such as anemia and thrombocytopenia, and childhood‑onset growth abnormalities. Affected individuals may show reduced thromboxane A₂ synthesis, leading to impaired platelet aggregation responses to arachidonic acid, although clinical bleeding is typically absent. Biallelic loss‑of‑function variants in TBXAS1 impair thromboxane synthase activity, altering prostaglandin and thromboxane metabolism and contributing to the characteristic combination of bone sclerosis and marrow dysfunction.