When stratified by GA (Table 4), extremely preterm infants (<28 weeks) demonstrated significant correlations between S100B and nadir SpO2 (ρ = −0.46 at SpO2 <85%; ρ = −0.46 at SpO2 <80%, both p <0.01) as well as IH duration (ρ = 0.37–0.42, p <0.05). The gene discussed is S100B; the disease is isolated hemihyperplasia.