Two missense mutations of EGR2 R359W and GJB1 V136A in a Charcot-Marie-Tooth disease family

During mutational analysis of Charcot-Marie-Tooth (CMT) causative genes, we identified a CMT family with two missense mutations in different genes. A R359W mutation in EGR2 was shared by the affected daughter (proband) and her father. In addition, she had a V136A mutation in GJB1, which was determined to be a de novo mutation. The daughter with two different gene mutations showed more severe clinical, electrophysiological and histopathological phenotypes than her father who had only the EGR2 mutation. We suggest that these phenotypic differences between the proband and her father may have been caused by an altered effect of the genetic modifier in EGR2, or by the additive effect of the EGR2 and GJB1 mutations.