Quantitative fluorescence-polymerase chain reaction assay for the detection of the duplication of the Charcot Marie Tooth disease type 1A critical region.
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.
De Toffol
Simona
S
Unit of Research and Development, Cytogenetics, and Molecular Biology, TOMA Advanced Biomedical Assays SpA, Busto Arsizio, Varese, Italy.
Bellone
Emilia
E
Dulcetti
Francesca
F
Ruggeri
Anna Maria
AM
Maggio
Pietro Paolo
PP
Pulimeno
Maria Rosaria
MR
Mandich
Paola
P
Maggi
Federico
F
Simoni
Giuseppe
G
Grati
Francesca Romana
FR
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
D017931:DNA Primers; D005819:Genetic Markers; D009185:Myelin Proteins; C073687:PMP22 protein, human