µLAS: Sizing of expanded trinucleotide repeats with femtomolar sensitivity in less than 5 minutes

• Published in: Scientific reports 2019-01, Vol.9 (1), p.23, Article 23
• Main Authors: Malbec, Rémi, Chami, Bayan, Aeschbach, Lorène, Ruiz Buendía, Gustavo A., Socol, Marius, Joseph, Pierre, Leïchlé, Thierry, Trofimenko, Evgeniya, Bancaud, Aurélien, Dion, Vincent
• Format: Article
• Language: English
• Subjects: 45/29; 45/41; 45/62; 631/1647/2196; 631/45/147; Alleles; Artefacts; Biochemistry, Molecular Biology; Deoxyribonucleic acid; Diagnostic Tests, Routine - methods; DNA; Dystrophy; Engineering Sciences; Genomics; Humanities and Social Sciences; Humans; Lab-on-a-chip; Lab-On-A-Chip Devices; Life Sciences; Micro and nanotechnologies; Microelectronics; Molecular biology; multidisciplinary; Myotonic dystrophy; Nervous System Diseases - diagnosis; Nervous System Diseases - pathology; Neurological diseases; Neuromuscular diseases; Neuromuscular Diseases - diagnosis; Neuromuscular Diseases - pathology; Polyglutamine; Science; Science (multidisciplinary); Sensitivity and Specificity; Trinucleotide repeat diseases; Trinucleotide Repeat Expansion; Trinucleotide repeats
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-36632-5

We present µLAS, a lab-on-chip system that concentrates, separates, and detects DNA fragments in a single module. µLAS speeds up DNA size analysis in minutes using femtomolar amounts of amplified DNA. Here we tested the relevance of µLAS for sizing expanded trinucleotide repeats, which cause over 20 different neurological and neuromuscular disorders. Because the length of trinucleotide repeats correlates with the severity of the diseases, it is crucial to be able to size repeat tract length accurately and efficiently. Expanded trinucleotide repeats are however genetically unstable and difficult to amplify. Thus, the amount of amplified material to work with is often limited, making its analysis labor-intensive. We report the detection of heterogeneous allele lengths in 8 samples from myotonic dystrophy type 1 and Huntington disease patients with up to 750 CAG/CTG repeats in five minutes or less. The high sensitivity of the method allowed us to minimize the number of amplification cycles and thus reduce amplification artefacts without compromising the detection of the expanded allele. These results suggest that µLAS can speed up routine molecular biology applications of repetitive sequences and may improve the molecular diagnostic of expanded repeat disorders.