Charcot-Marie-Tooth disease type I and related demyelinating neuropathies: Mutation analysis in a large cohort of Italian families

Hum Mutat. 2001;18(1):32-41. doi: 10.1002/humu.1147.


Charcot-Marie-Tooth neuropathy type 1 (CMT1), the most common hereditary neurological disorder in humans, is characterized by clinical and genetic heterogeneity. It is caused mainly by a 1.5 Mb duplication in 17p11.2, but also by mutations in the myelin genes PMP22 (peripheral myelin protein 22), MPZ (myelin protein zero), Cx32 (connexin 32; also called GJB1), and EGR2 (early growth response 2). In this study, we have screened 172 index cases of Italian families in which there was at least one subject with a CMT1 diagnosis for the duplication on 17p11.2 and mutations in these genes. Among 170 informative unrelated patients, the overall duplication frequency was 57.6%. A difference could be observed between the duplication frequency in familial cases (71.6%) and that observed in non-familial cases (36.8%). Among the non-duplicated patients, 12 were mutated in Cx32, four in MPZ, two in PMP22, and none in the EGR2. In the non-duplicated cases, the overall point mutation frequency for these genes was 25.0%. We describe the mutations identified, and consider possible genotype-phenotype correlation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Charcot-Marie-Tooth Disease / classification
  • Charcot-Marie-Tooth Disease / genetics*
  • Chromosomes, Human, Pair 17 / genetics*
  • Cohort Studies
  • Connexins / genetics
  • DNA Mutational Analysis
  • Gap Junction beta-1 Protein
  • Gene Duplication
  • Gene Frequency / genetics
  • Genes, Duplicate / genetics*
  • Genetic Testing
  • Genotype
  • Hereditary Sensory and Motor Neuropathy / genetics*
  • Humans
  • Italy
  • Mutation / genetics*
  • Myelin P0 Protein / genetics
  • Myelin Proteins / genetics
  • Phenotype
  • Point Mutation / genetics


  • Connexins
  • Myelin P0 Protein
  • Myelin Proteins
  • PMP22 protein, human