NGF and staphylococcus aureus infection: HSAN5 is characterised by the selective loss of unmyelinated C fibres and myelinated Aδ fibres,15, –17 lack of pain perception and recurrent injuries as well as a susceptibility towards Staphylococcus aureus infections.18 To date, two mutations in NGF have been identified: p.R221W and p.V232fs.15,19 Assessment of these two NGF mutations showed that the original mutation, p.R221W, resulted in reduced processing of NGF, whilst the second mutation, p.V232fs, abolished processing and altered neurotrophic activity.19,20