Mutations in MME gene has previously been reported to cause autosomal recessive (AR) Charcot-Marie-Tooth disease type 2 (CMT2) and also to be associated with late-onset autosomal dominant (AD) polyneuropathies. In our cohort, we found that MME mutations co-segregated with the disease following an exclusive AR pattern of inheritance. Moreover, patients carrying heterozygous mutations in our study show great phenotypic heterogeneity, which argues against its pathogenic role. Our study provides a very good example of how careful segregations studies can be crucial in determining pathogenicity of mutations associated with late onset neuropathies. (By Dr. Vincenzo Lupo, https://jmg.bmj.com/content/early/2018/11/10/jmedgenet-2018-105650 )