Nanopore Sequencing Improves Diagnosis of Tandem Repeat Expansion Diseases

Types of Genomic Diseases

There’s no limit to the variety of biological problems our clients are tackling with bioinformatics. Often, researchers are investigating diseases that are caused by mutations in just one or a couple of genes, and use bioinformatics to identify causative mutations.

However, there are also genomic diseases caused by macro, structural-level changes to the genome. These include copy number variations, where there are extra copies of genes, or extra copies of whole chromosomes like trisomy 21, which causes Down syndrome.

What are Tandem Repeat Expansions?

One of these structural variants is called a tandem repeat, short repeated sequences that are common sources of human genetic variation. However, increased copies of tandem repeats, called tandem repeat expansion, is a cause of numerous neurological conditions.

Therapeutics for these types of neurological conditions have to be specifically tailored to the type of tandem repeat expansion present, requiring accurate diagnosis. Due to the unique biochemistry of tandem repeats and the fact that they often present at multiple loci in the genome, traditional techniques like PCR are time-consuming and have poor efficacy.

Improved Diagnostics Using Nanopore Sequencing

In a recent paper published in npj Genomic Medicine, the authors detailed a new, more accurate diagnostic method for tandem repeat expansion-based diseases using nanopore sequencing. In this application in particular, nanopore sequencing has the advantage of being faster, more direct and more accurate than traditional diagnostic methods.

Across 12 patients with molecularly-confirmed tandem repeat expansion-based diseases, their mew method accurately diagnosed all 12. When applied to a group of 10 patients exhibiting symptoms consistent with this type of neurologic disease, the nanopore-based method correctly diagnosed all 10 patients and corrected two inaccurate diagnoses from conventional methods.

Outsourcing Bioinformatics Analysis: How We Can Help

From investigating single nucleotide polymorphisms to structural genomic variation, transforming raw sequence data of any kind into actionable biological insights is no small feat. As experts across data types from cutting-edge sequencing platforms, we can help you tackle the challenging computational tasks of storing, analyzing and interpreting genomic data. Bridge Informatics’ bioinformaticians are trained bench biologists, so they understand the biological questions driving your computational analysis. Click here to schedule a free introductory call with a member of our team.

Jane Cook, Biochemist & Content Writer, Bridge Informatics

Jane Cook, leading Content Writer for Bridge Informatics, has written over 100 articles on the latest topics and trends for the bioinformatics community. Jane’s broad and deep interdisciplinary molecular biology experience spans developing biochemistry assays to genomics. Prior to joining Bridge, Jane held research assistant roles in biochemistry research labs across a variety of therapeutic areas. While obtaining her B.A. in Biochemistry from Trinity College in Dublin, Ireland, Jane also studied journalism at New York University’s Arthur L. Carter Journalism Institute. As a native Texan, she embraces any challenge that comes her way. Jane hails from Dallas but returns to Ireland any and every chance she gets. If you’re interested in reaching out, please email or

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