SMN2 and spinal muscular atrophy, type 1: The range of pNFH neurofilament levels in the cerebrospinal fluid before treatment was quite wide, ranging from 0.035 ng/dL in a 104-month-old patient with 3 SMN2 copies, diagnosed with SMA type 2, to 3.321 ng/dL in a 3.63-months-old patient diagnosed with SMA type 1 with 2 SMN2 copies, the patient with one of the most severe forms of the disease.