A Novel Triplet-Primed PCR Assay to Detect the Full Range of Trinucleotide CAG Repeats in the Huntingtin Gene ()

Overview

Journal Int J Mol Sci

Publisher MDPI

Specialties Biochemistry
Chemistry
Molecular Biology

Date 2021 Feb 11

PMID 33567536

Citations 10

Authors

Alessandro De Luca

Annunziata Morella

Federica Consoli

Sergio Fanelli

Julie R Thibert

Sarah Statt

Gary J Latham

Ferdinando Squitieri

Affiliations

Soon will be listed here.

Abstract

The expanded CAG repeat number in gene causes Huntington disease (HD), which is a severe, dominant neurodegenerative illness. The accurate determination of the expanded allele size is crucial to confirm the genetic status in symptomatic and presymptomatic at-risk subjects and avoid genetic polymorphism-related false-negative diagnoses. Precise CAG repeat number determination is critical to discriminate the cutoff between unexpanded and intermediate mutable alleles (IAs, 27-35 CAG) as well as between IAs and pathological, low-penetrance alleles (i.e., 36-39 CAG repeats), and it is also critical to detect large repeat expansions causing pediatric HD variants. We analyzed the -CAG repeat number of 14 DNA reference materials and of a DNA collection of 43 additional samples carrying unexpanded, IAs, low and complete penetrance alleles, including large (>60 repeats) and very large (>100 repeats) expansions using a novel triplet-primed PCR-based assay, the AmplideX PCR/CE Kit. The results demonstrate that the method accurately genotypes both normal and expanded -CAG repeat numbers and reveals previously undisclosed and very large CAG expansions >200 repeats. We also show that this technique can improve genetic test reliability and accuracy by detecting CAG expansions in samples with sequence variations within or adjacent to the repeat tract that cause allele drop-outs or inaccuracies using other PCR methods.

Citing Articles

Ascertainment of uninterrupted CAG repeat length and disease-modifying variants in fragment-based genetic testing for Huntington Disease.

Findlay Black H, Kay C, Dawson J, Bortnick S, Javier K, Xia Q Genet Med Open. 2024; 2:101882.

PMID: 39669608 PMC: 11613659. DOI: 10.1016/j.gimo.2024.101882.

Beyond CAG Repeats: The Multifaceted Role of Genetics in Huntington Disease.

Pengo M, Squitieri F Genes (Basel). 2024; 15(6).

PMID: 38927742 PMC: 11203031. DOI: 10.3390/genes15060807.

Clinical Review of Juvenile Huntington's Disease.

Oosterloo M, Touze A, Byrne L, Achenbach J, Aksoy H, Coleman A J Huntingtons Dis. 2024; 13(2):149-161.

PMID: 38669553 PMC: 11307030. DOI: 10.3233/JHD-231523.

A deep population reference panel of tandem repeat variation.

Ziaei Jam H, Li Y, DeVito R, Mousavi N, Ma N, Lujumba I Nat Commun. 2023; 14(1):6711.

PMID: 37872149 PMC: 10593948. DOI: 10.1038/s41467-023-42278-3.

A deep population reference panel of tandem repeat variation.

Ziaei Jam H, Li Y, DeVito R, Mousavi N, Ma N, Lujumba I bioRxiv. 2023; .

PMID: 36945429 PMC: 10028971. DOI: 10.1101/2023.03.09.531600.

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