scholarly journals Polymorphic Short Tandem Repeats for Diagnosis of the Charcot-Marie-Tooth 1A Duplication

2001 ◽  
Vol 47 (5) ◽  
pp. 829-837 ◽  
Author(s):  
Philippe Latour ◽  
Laetitia Boutrand ◽  
Nicolas Levy ◽  
Rafaëlle Bernard ◽  
Amandine Boyer ◽  
...  
Keyword(s):  
Short Tandem Repeats ◽  
Tandem Repeats ◽  
Fluorescence Labeling ◽  
Diagnostic Strategy ◽  
Peripheral Myelin Protein 22 ◽  
Charcot Marie Tooth ◽  
Charcot Marie Tooth Disease ◽  
Combined Use ◽  
Tooth Disease ◽  
Short Tandem

Abstract Background: A 1.5-Mb microduplication containing the gene for peripheral myelin protein 22 (PMP22) on chromosome 17p11.2-12 is responsible for 75% of cases of the demyelinating form of Charcot-Marie-Tooth disease (CMT1A). Methods for molecular diagnosis of CMT1A use Southern blot and/or amplification by PCR of polymorphic poly(AC) repeats (microsatellites) located within the duplicated region, or the detection of junction fragments specific for the duplication. Difficulties with both strategies have led us to develop a new diagnostic strategy with highly polymorphic short tandem repeats (STRs) located inside the CMT1A duplicated region. Methods: We tested 10 STRs located within the duplication for polymorphic behavior. Three STRs were selected and used to test a set of 130 unrelated CMT1A patients and were compared with nonduplicated controls. The study was then extended to a larger population of patients. Alleles of interest were sequenced. A manual protocol using polyacrylamide electrophoresis and silver staining and an automated capillary electrophoresis protocol to separate fluorescently labeled alleles were validated. Results: We identified three new STRs covering 0.55 Mb in the center of the CMT1A duplication. One marker, 4A, is located inside the PMP22 gene. The two others, 9A and 9B, more telomerically positioned, have the highest observed heterozygosity reported to date for CMT1A markers: 0.80 for 9A, and 0.79 for 9B. Tetra- and pentanucleotide repeats offered clear amplification, accurate sizing, and easy quantification of intensities. Conclusions: Combined use of the three STRs allows robust diagnosis with almost complete informativeness. In our routine diagnosis for CMT1A, they have replaced the use of other polymorphic markers, either in a manual adaptation or combined with fluorescence labeling and allele sizing on a DNA sequencer.

scholarly journals New Polymorphic Short Tandem Repeats for PCR-based Charcot-Marie-Tooth Disease Type 1A Duplication Diagnosis

2001 ◽  
Vol 47 (5) ◽  
pp. 838-843 ◽  
Author(s):  
Jose L Badano ◽  
Ken Inoue ◽  
Nicholas Katsanis ◽  
James R Lupski
Keyword(s):  
Short Tandem Repeats ◽  
Tandem Repeats ◽  
Genomic Sequence ◽  
Disease Type ◽  
Charcot Marie Tooth ◽  
Charcot Marie Tooth Disease ◽  
Allele Dosage ◽  
Pulsed Field Electrophoresis ◽  
Tooth Disease ◽  
Short Tandem

Abstract Background: Charcot-Marie-Tooth disease type 1A (CMT1A) accounts for 70–90% of cases of CMT1 and is most frequently caused by the tandem duplication of a 1.4-Mb genomic fragment on chromosome 17p12. Molecular diagnosis of CMT1A has been based primarily on pulsed-field electrophoresis, fluorescence in situ hybridization, polymorphic allele dosage analysis, and quantitative PCR. We sought to improve the fidelity and applicability of PCR-based diagnosis by developing a panel of novel, highly polymorphic short tandem repeats (STRs) from within the CMT1A duplicated region. Methods: We used a recently available genomic sequence to identify potentially polymorphic simple repeats. We then amplified these sequences in a multiethnic cohort of unaffected individuals and assessed the heterozygosity and number of alleles for each STR. Highly informative markers were then tested in a set of previously diagnosed CMT1A duplication patients, and the ability to identify the genomic duplication through the presence of three bands was assessed. Results: We identified 34 polymorphic markers, 15 of which were suitable for CMT1A diagnosis on the basis of high heterozygosity in different ethnic groups, peak uniformity, and a large number of alleles. On the basis of the fluorescent dye and allele range of each marker, we developed two panels, each of which could be analyzed concurrently. Panel 1, which comprised 10 markers, detected 37 of 39 duplications, whereas panel 2, which comprised the remaining 5 markers, identified 21 of 39 duplications. Through the combination of both panels, we identified 39 of 39 duplications in previously diagnosed CMT1A patients. Conclusions: The newly developed 15-marker set has the capability of detecting >99% of duplications and thus is a powerful and versatile diagnostic tool.

A novel diagnostic strategy for trisomy 21 using short tandem repeats

2006 ◽  
Vol 27 (2) ◽  
pp. 416-422 ◽  
Author(s):  
Jing Yan ◽  
Jin Wu ◽  
Yingbi Li ◽  
He Wang ◽  
Zhongying Huang ◽  
...  
Keyword(s):  
Trisomy 21 ◽  
Short Tandem Repeats ◽  
Tandem Repeats ◽  
Diagnostic Strategy ◽  
Short Tandem

scholarly journals Direct relationship between increased expression and mistrafficking of the Charcot–Marie–Tooth–associated protein PMP22

2020 ◽  
Vol 295 (34) ◽  
pp. 11963-11970 ◽  
Author(s):  
Justin T. Marinko ◽  
Bruce D. Carter ◽  
Charles R. Sanders
Keyword(s):  
Dermal Fibroblasts ◽  
Rodent Models ◽  
Chromosome Fragment ◽  
Peripheral Myelin Protein 22 ◽  
Charcot Marie Tooth ◽  
Charcot Marie Tooth Disease ◽  
Cell Flow Cytometry ◽  
Endoplasmic Reticulum Quality Control ◽  
The Relationship ◽  
Tooth Disease

Charcot–Marie–Tooth disease (CMT) is a neuropathy of the peripheral nervous system that afflicts ∼1:2500 people. The most common form of this disease (CMT1A, 1:4000) is associated with duplication of chromosome fragment 17p11.2-12, which results in a third WT PMP22 allele. In rodent models overexpressing the PMP22 (peripheral myelin protein 22) protein and in dermal fibroblasts from patients with CMT1A, PMP22 aggregates have been observed. This suggests that overexpression of PMP22 under CMT1A conditions overwhelms the endoplasmic reticulum quality control system, leading to formation of cytotoxic aggregates. In this work, we used a single-cell flow-cytometry trafficking assay to quantitatively examine the relationship between PMP22 expression and trafficking efficiency in individual cells. We observed that as expression of WT or disease variants of PMP22 is increased, the amount of intracellular PMP22 increases to a greater extent than the amount of surface-trafficked protein. This was true for both transiently transfected cells and PMP22 stable expressing cells. Our results support the notion that overexpression of PMP22 in CMT1A leads to a disproportionate increase in misfolding and mistrafficking of PMP22, which is likely a contributor to disease pathology and progression.

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