Comparing mean NFL concentrations for each of the 142 patients with COVID-19 to NFL concentrations of the 55 controls revealed that serum NFL was significantly higher in patients (median, 29.4 pg/ml; range, 3.4 to 1538.4 pg/ml) than controls (median, 10.9 pg/ml; range, 3.2 to 43.2 pg/ml; P < 0.001; Fig. 1A). The gene discussed is NEFL; the disease is COVID-19.