Most studies have focused on comparing NfL levels between different NDs and controls8, 9, 10, 11, 12, 13 Some studies have investigated CSF and blood NfL for broad ND diagnosis in clinical settings, finding elevated concentrations of NfL in ND, diagnostic utility, and/or increasing diagnostic certainty.14, 15, 16, 17, 18, 19, 20. The gene discussed is NEFL; the disease is Norrie disease.