OS, such as accumulation of heme oxygenase-1 (HO-1) and superoxide dismutase in microglia, nitrotyrosine and 4-hydroxynonal in neurons, and induction of endothelial nitric oxide synthase (NOS) in vulnerable areas, particularly the thalamus, are significant neurological characteristics of TD (Calingasan and Gibson, 2000). The gene discussed is HMOX1; the disease is thanatophoric dysplasia.