Fig. 2

Mapping of missense SCN9A-gene mutation sites around NaV1.7’s pore. a Mapping of missense SCN9A-gene mutation sites for \({\mathbf{p}}\in P\) and \(\alpha =1,2,\ldots ,K_{\alpha }=800\). Two sets of missense SCN9A-gene mutation sites are employed; a pain-related set containing IEM, PPD and SFN mutation sites, and a neutral set containing mutation sites which are not expected to associate with pain disease phenotypes (Additional file 1: S8). Scaling indices lines \(\alpha _{s}\), \(\alpha _{\xi }\) and \(\alpha _{o}\) highlight the boundaries among consecutive atom-packing domains. Specifically, \(\alpha _{s}\) denotes the ending and beginning of the lag and inflection domain, respectively. \(\alpha _{o}\) denotes the ending and beginning of the inflection and asymptote domain, respectively. \(\alpha _{\xi }\) denotes the location of inflection points and the ending and beginning of the first and second part of the inflection domain, respectively. Labels “a1”, “a2”, and “a3” indicate map areas where the number of mutation sites maximizes, i.e., mutation sites occupancy rates maximize. a Map occupancy rate of mutation sites along \(\alpha\)-direction. c Map occupancy rate of mutation sites along \({\mathbf{p}}\)-direction. Red- and blue-colored histograms account for map occupancy rates of pain-related, and neutral mutation sites, respectively