DNA sequencing analysis of SCN9A and FKBP1b. The FKBP1b gene was mutated to a C deletion at location 137 in exon 3 resulting in complexed amino acid changes. The amino acid change was proline to leucine at position 46; the next 22 amino acids were framed shifted culminating in a stop codon 22 amino acides downstream (P46L fsx22). The SCN9A gene was mutated from a T to C substitution at position 3253 in exon 17, resulting in an amino acid change from serine to proline at position 1085 (S1085P). The PXDNL gene was mutated from a G to A at position 1172 in exon 14, resulting in an amino acid change from arginine to glutamine at position 391 (R391Q). Mutations in SCN9A and FKBP1b are highly conserved across the various species. PXDNL is only expressed in certain mammals including primates.