We describe here a CMT1 family (a 63-year-old man, his brother and his niece) in which two mutations on different chromosomes were found in the PMP22 gene, the 17p duplication, detected by fluorescent semiquantitative polymerase chain reaction (PCR) of microsatellite markers localized within the duplicated region on chromosome 17p11.2-p12, and the Thr(118)Met substitution, detected by direct sequencing the four coding exons of the PMP22 gene.
The major Charcot- Marie-Tooth Type 1 (CMT1) locus, CMT1A, and Hereditary neuropathy with liability to pressure palsies (HNPP) cosegregate with a 1.5-Mb duplication and a 1.5-Mb deletion, respectively, in band 17p11.2.
The CMT loci are known to map to chromosome 1 (CMT1B), chromosome 17 (CMT1A), the X chromosome (CMTX), and two additional unknown autosomes (CMT1C and CMT2).
To determine the clinical, electrophysiologic, and morphologic characteristics of a consanguineous Moroccan family with ARCMT disease associated with the S194X mutation in the GDAP1 gene.
These results confirm the leading role of PMP22 mutation analysis in the differential diagnosis of CMT and show that the spectrum and frequency of PMP22 mutations in the Slovak population is comparable to that seen in the global population.
Charcot-Marie-Tooth disease (CMT) is a genetically heterogeneous disorder that has been associated with alterations of several proteins: peripheral myelin protein 22, myelin protein zero, connexin 32, early growth response factor 2, periaxin, myotubularin related protein 2, N-myc downstream regulated gene 1 product, neurofilament light chain, and kinesin 1B.
Charcot-Marie-Tooth disease (CMT) is a group of clinically and genetically heterogeneous neuropathies classically divided into demyelinating (CMT1) and axonal forms (CMT2).
These observations highlight the wide spectrum of CMT1A and the overlap between CMT1A and HNPP (both linked to the PMP22 gene), and finally illustrate the complexity of the genotype-phenotype correlations in Charcot-Marie-Tooth diseases.
Recently, this has also been observed in mice mildly overexpressing human peripheral myelin protein 22 kD mimicking the most common form of CMT, CMT type 1A.
Mutations in three genes coding for the myelin proteins peripheral myelin protein 22, myelin protein zero and connexin 32 and in one gene coding for the transcription factor early growth response 2 element are associated with Charcot-Marie-Tooth type 1 and 2, hereditary neuropathy with liability to pressure palsies, Dejerine-Sottas syndrome and congenital hypomyelination.
We report on a 20-year-old male with severe Charcot-Marie-Tooth (CMT) disease and a de novo deletion (c.281delG, p.G94AfsX17) on the paternal PMP22 allele harboring c.353C>T (p.T118M).
Charcot-Marie-Tooth neuropathy type 1 (CMT1) is a genetically heterogeneous group of chronic demyelinating polyneuropathies with loci mapping to chromosome 17 (CMT1A), chromosome 1 (CMT1B), the X chromosome (CMTX) and to another unknown autosome (CMT1C).