Table 3.

NF assay validation studies: Group questions and answers from surveys four-six

Question	Common Advisor Answers
Would you prefer to assay NF-L or NF-H?	Both NF-L and NF-H
What biofluid sample should be collected?	Blood should be prioritized over CSF
Over what period of time should longitudinal samples be collected?	Varies depending on subject age
What ages should be studied?	0–10 years old; adults; determine SMA natural history
How many subjects should be included?	Unknown
How many total studies will need to be conducted?	Approximately 10
What outcomes should be measured against NF levels to support validation of the biomarker?	Motor function, CMAP, SMN protein levels, SMN2 copy number
Should healthy volunteers be included?	Yes, to determine thresholds and normal variation
What additional questions should the validation studies address?	•Can the assay be multiplexed with other assays in the future?
	•Cost, ease of use, possibility of utilizing a commercial laboratory
	•Sample volume needed for readout
	•Reproducibility and biologic variation