title: Quantitative fluorescence-polymerase chain reaction assay for the detection of the duplication of the Charcot Marie Tooth disease type 1A critical region.
abstract: Charcot Marie Tooth (CMT) syndrome is the most common hereditary peripheral neuropathy, with an incidence of about 1 in 2500. The subtype 1A (CMT1A) is caused by a tandem duplication of a 1.5-Mb region encompassing the PMP22 gene. Conventional short tandem repeat (STR) analysis can reveal this imbalance if a triallelic pattern, defining with certainty the presence of duplication, is present. In case of duplication with a biallelic pattern, it can only indicate a semiquantitative dosage of the fluorescence intensity ratio of the two fragments. In this study we developed a quantitative fluorescence-PCR using seven highly informative STRs within the CMT1A critical region that successfully disclosed or excluded the presence of the pathogenic imbalance in a cohort of 60 samples including 40 DNAs from samples with the CMT1A duplication previously characterized with two different molecular approaches, and 20 diagnostic samples from 10 members of a five-generation pedigree segregating CMT1A, 8 unrelated cases and 2 prenatal samples. The application of the quantitative fluorescence-PCR using STRs located in the critical region could be a reliable method to evaluate the presence of the PMP22 duplication for the diagnosis and classification of hereditary neuropathies in asymptomatic subjects with a family history of inherited neuropathy, in prenatal samples in cases with one affected parent, and in unrelated patients with a sporadic demyelinating neuropathy with clinical features resembling CMT (i.e., pes cavus with hammer toes) or with conduction velocities in the range of CMT1A.
authors.affiliation: Unit of Research and Development, Cytogenetics, and Molecular Biology, TOMA Advanced Biomedical Assays SpA, Busto Arsizio, Varese, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: De Toffol
authors.forename: Emilia
authors.initials: E
authors.lastname: Bellone
authors.forename: Francesca
authors.initials: F
authors.lastname: Dulcetti
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Ruggeri
authors.forename: Pietro Paolo
authors.initials: PP
authors.lastname: Maggio
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Pulimeno
authors.forename: Paola
authors.initials: P
authors.lastname: Mandich
authors.forename: Federico
authors.initials: F
authors.lastname: Maggi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Simoni
authors.forename: Francesca Romana
authors.initials: FR
authors.lastname: Grati
mesh_terms: D000328:Adult; D001483:Base Sequence; D002607:Charcot-Marie-Tooth Disease / Q000145:classification / Q000175:diagnosis* / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005819:Genetic Markers; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D009185:Myelin Proteins / Q000235:genetics; D010375:Pedigree; D016133:Polymerase Chain Reaction / Q000379:methods*; D011247:Pregnancy
chemical_list: D017931:DNA Primers; D005819:Genetic Markers; D009185:Myelin Proteins; C073687:PMP22 protein, human