Objective: To establish the gene diagnosis of chavcot-Marie-Tooth disease (CMT) by (PCR) polymerase chain reaction and to study the molecular genetic characteristics of the Chinese CMT.
Methods: Mutation analysis of the Cx32, MPZ and PMP22 genes were performed by PCR-RFLP, PCR-SSCP, PCR-DGGE and/or direct sequencing in 32 CMT probands of the Hans in China.
Results: 21.9% of the CMT pedigrees had mutations in the Cx32, MPZ and PMP22 genes. Ten kinds of abnormal bands were found by PCR-SSCP, including 5 kinds of polymorphism and 5 point mutations in the exons of the gene (4 of the Cx32 and 1 of the MPZ). No point mutation of the PMP22 gene was found in these patients but two families (6.3%) were diagnosed as CMT1A by the PCR-RFLP, with the tandem repeat mutation of 1.5 Mb including the PMP22 gene.
Conclusion: PCR-SSCP and PCR-RFLP are the first two screening methods in the gene diagnosis of CMT. PCR-DGGE is not appropriate for mutation analysis of Cx32. The point mutations must be certificated by sequencing. The mutation screening in the possible X-linkage family has to start with Cx32 gene.