Mutations in the gene encoding filaggrin (FLG) have been identified as the cause of ichthyosis vulgaris (IV) and shown to be major predisposing factors for atopic dermatitis. The profilaggrin protein consists of 10-12 filaggrin monomer repeats arranged in tandem, which arise from an ultra-long sequence of exon 3 comprised of near-indistinguishable repeats, demonstrating intragenic copy number variations (CNVs). As such, it was not until 2006 that null mutations in FLG could be detected using the newly developed long-range polymerase chain reaction (PCR) technique. However, this technique is labor-intensive, time-consuming and costly. Nanopore sequencing is a third-generation sequencing technology with ability to sequence longer reads of DNA and RNA in real-time. In the present study, five Taiwanese IV patients were recruited. We applied nanopore sequencing for detecting FLG CNVs, yielding concordant results with those obtained from traditional PCR. Mutation analysis with nanopore sequencing revealed compatible mutation status with those unveiled by PCR-based Sanger sequencing. We subsequently estimated the total cost and time required in our lab for sequencing the entire FLG using PCR-based Sanger sequencing, whole-exome sequencing or nanopore sequencing. The last accounts for around 1/5 of the cost and less than 1/3 of the time when compared with the first. Herein, we propose that nanopore sequencing has the potential to be a more cost-effective and time-efficient technique for conducting molecular analysis, particularly for the detection of CNVs and null mutations in patients with IV.

ESDR293 - Application of nanopore sequencing in identifying null mutations and intragenic copy number variations in filaggrin gene

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.