Baldwin et al, reported their results from a GWAS of CALGB40101 and the top associations were with SNPs in FDG4, EPHA5, and FZD3; although the first two did not meet genome wide significance.[7] The FGD4 variant from the CALGB40101 EA discovery set was replicated in a small cohort of AA patients.[7] Both FGD4 and SBF2 are known to be associated with subtype 4 CMT.[20] Few prior studies have tested for the effect of rare variants across the exome or genome on TIPN. This evidence concerns the gene SBF2 and Charcot-Marie-Tooth disease.