Molecular analyses of unrelated Charcot-Marie-Tooth (CMT) disease patients suggest a high frequency of the CMT1A duplication

• Published in: American journal of human genetics 1993-10, Vol.53:4
• Main Authors: Wise, C.A., Davis, S.N., Heju, Z., Pentao, L., Patel, P.I., Lupski, J.R., Garcia, C.A.
• Format: Article
• Language: English
• Subjects: BASIC BIOLOGICAL SCIENCES; CHROMOSOMAL ABERRATIONS; CHROMOSOMES; DISEASES; DNA SEQUENCING; GENE AMPLIFICATION; GENE MUTATIONS; HUMAN CHROMOSOME 17; HUMAN CHROMOSOMES; MUTATIONS; NERVOUS SYSTEM DISEASES; STRUCTURAL CHEMICAL ANALYSIS 550400 > Genetics
• ISSN: 0002-9297; 1537-6605

Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral neuropathy. One form of CMT, CMT type 1A, is characterized by uniformly decreased nerve conduction velocities, usually shows autosomal dominant inheritance, and is associated with a large submicroscopic duplication of the p11.2-p12 region of chromosome 17. A cohort of 75 unrelated patients diagnosed clinically with CMT and evaluated by electrophysiological methods were analyzed molecularly for the presence of the CMT1A DNA duplication. Three methodologies were used to assess the duplication: Measurement of dosage differences between RFLP alleles, analysis of polymorphic (GT)[sub n] repeats, and detection of a junction fragment by pulsed-field gel electrophoresis. The CMT1A duplication was found in 68% of the 63 unrelated CMT patients with electrophysiological studies consistent with CMT type 1 (CMT1). The CMT1A duplication was detected as a de novo event in two CMT1 families. Twelve CMT patients who did not have decreased nerve conduction velocities consistent with a diagnosis of CMT type 2 (CMT2) were found not to have the CMT1A duplication. The most informative molecular method was the detection of the CMT1A duplication-specific junction fragment. Given the high frequency of the CMT1A duplication in CMT patients and the high frequency of new mutations, the authors conclude that a molecular test for the CMT1A DNA duplication is very useful in the differential diagnosis of patients with peripheral neuropathies. 61 refs., 4 figs.