Login / Signup

Long-read targeted sequencing uncovers clinicopathological associations for C9orf72-linked diseases.

Mariely DeJesus-HernandezRoss A AleffJazmyne L JacksonNiCole A FinchMatthew C BakerTania F GendronMelissa E MurrayIan J McLaughlinJohn R HartingNeill R Graff-RadfordBjörn E OskarssonDavid S KnopmanKeith Anthony JosephsBradley F BoeveRonald C PetersenJohn D FryerLeonard PetrucelliGourisankar GhoshRosa RademakersMark T W EbbertEric D WiebenMarka van Blitterswijk
Published in: Brain : a journal of neurology (2021)
To examine the length of a hexanucleotide expansion in C9orf72, which represents the most frequent genetic cause of frontotemporal lobar degeneration and motor neuron disease, we employed a targeted amplification-free long-read sequencing technology: No-Amp sequencing. In our cross-sectional study, we assessed cerebellar tissue from 28 well-characterized C9orf72 expansion carriers. We obtained 3507 on-target circular consensus sequencing reads, of which 814 bridged the C9orf72 repeat expansion (23%). Importantly, we observed a significant correlation between expansion sizes obtained using No-Amp sequencing and Southern blotting (P = 5.0 × 10-4). Interestingly, we also detected a significant survival advantage for individuals with smaller expansions (P = 0.004). Additionally, we uncovered that smaller expansions were significantly associated with higher levels of C9orf72 transcripts containing intron 1b (P = 0.003), poly(GP) proteins (P = 1.3 × 10- 5), and poly(GA) proteins (P = 0.005). Thorough examination of the composition of the expansion revealed that its GC content was extremely high (median: 100%) and that it was mainly composed of GGGGCC repeats (median: 96%), suggesting that expanded C9orf72 repeats are quite pure. Taken together, our findings demonstrate that No-Amp sequencing is a powerful tool that enables the discovery of relevant clinicopathological associations, highlighting the important role played by the cerebellar size of the expanded repeat in C9orf72-linked diseases.
Keyphrases
  • single cell
  • protein kinase
  • healthcare
  • small molecule
  • pet ct
  • drug delivery
  • clinical practice
  • health insurance
  • high throughput sequencing