TY - JOUR
T1 - Long-read targeted sequencing uncovers clinicopathological associations for C9orf72-linked diseases
AU - Dejesus-Hernandez, Mariely
AU - Aleff, Ross A.
AU - Jackson, Jazmyne L.
AU - Finch, Nicole A.
AU - Baker, Matthew C.
AU - Gendron, Tania F.
AU - Murray, Melissa E.
AU - McLaughlin, Ian J.
AU - Harting, John R.
AU - Graff-Radford, Neill R.
AU - Oskarsson, Björn
AU - Knopman, David S.
AU - Josephs, Keith A.
AU - Boeve, Bradley F.
AU - Petersen, Ronald C.
AU - Fryer, John D.
AU - Petrucelli, Leonard
AU - DIckson, Dennis W.
AU - Rademakers, Rosa
AU - Ebbert, Mark T.W.
AU - Wieben, Eric D.
AU - Van Blitterswijk, Marka
N1 - Publisher Copyright:
© 2021 The Author(s) (2021). Published by Oxford University Press on behalf of the Guarantors of Brain.
PY - 2021/4/1
Y1 - 2021/4/1
N2 - 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.
AB - 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.
KW - C9orf72
KW - amyotrophic lateral sclerosis
KW - frontotemporal lobar degeneration
KW - long-read sequencing
KW - motor neuron disease
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U2 - 10.1093/brain/awab006
DO - 10.1093/brain/awab006
M3 - Article
C2 - 33889947
AN - SCOPUS:85105905353
SN - 0006-8950
VL - 144
SP - 1082
EP - 1088
JO - Brain
JF - Brain
IS - 4
ER -