Re-analysis of an original CMTX3 family using exome sequencing identifies a known BSCL2 mutation.

INTRODUCTION Charcot-Marie-Tooth (CMT) disease is a group of peripheral neuropathies affecting both motor and sensory nerves. CMTX3 is an X-linked CMT locus, which maps to chromosome Xq26.3-q27.3. Initially, CMTX3 was mapped to a 31.2-Mb region in 2 American families. We have reexamined 1 of the original families (US-PED2) by next generation sequencing. METHODS Three members of the family underwent exome sequencing. Candidate variants were validated by PCR and Sanger sequencing analysis. CONCLUSION No pathogenic coding variants localizing to the CMTX3 region were identified. However, exome sequencing identified a known BSCL2 mutation (N88S). This study demonstrates the power of exome sequencing as a tool to identify gene mutations for a small family in the absence of statistically significant linkage data.