A point mutation in the human connexin32 promoter P2 does not correlate with X-linked dominant Charcot-Marie-Tooth neuropathy in Germany.

The sensorimotor neuropathy Charcot-Marie-Tooth disease (CMT) is the most common hereditary disorder of the peripheral nervous system. The X-linked dominant form of CMT (CMTX) is associated with mutations in the connexin32 gene (Cx32). The majority of CMTX cases harbour mutations in the coding region while a few cases have been reported to result from mutations in the promoter region. We found a G-713A transition of the nerve specific Cx32 promoter P2 in the Caucasian German population. The allele frequency reached 50%, both in CMT patients and in healthy control individuals. In contrast, in an earlier contribution to this journal [Brain Res. Mol. Brain Res.78 (2000) 146], the same base transition was reported to cause CMTX in a Taiwanese family. These divergent results are important for genetic counselling and require careful consideration of ethnic backgrounds and of diagnostic and experimental pitfalls.