Table 5 Recommendations on NP-C marker selection for following disease development or treatment efficacy

• NP-C disability scale based clinical measures are easy to use and broadly acknowledged.

• Simple, focussed NP-C disability scales (e.g. Pineda scale [45]) may be preferred over more wide-ranging measures (e.g., the NIH severity scale [90]).

• The efficient application of an NP-C marker as part of a research study does not guarantee that the marker will be useful in individual patients in a hospital setting.

• Imaging and laboratory marker methods should ideally be applied using established, locally available methods and expertise.

• Specific imaging markers (e.g., MRI, DTI, VFS) provide objective, quantitative data, and can be applied independently of patient age.

• The application of laboratory markers should be considered in relation to patients’ or carers’ acceptance and access.

• Diagnostic NP-C biomarkers (oxysterols, lysosphingolipids, bile acids) do not currently qualify as effective methods for disease monitoring over time.