NfL levels have been described to reflect inner retinal atrophy and neuroaxonal damage, in conditions like neurodegeneration,44, and multiple sclerosis.45 In addition, higher NfL levels were observed in children with acquired demyelination syndromes compared to infants with and without other neurological diseases.46,47 However, NfL levels in blood during the first years of life are affected by production, release, transportation and clearance and can thus reflect several conditions. The gene discussed is NEFL; the disease is multiple sclerosis.