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Detection of F8 int22h inversions using digital droplet PCR and mile-post assays

Manderstedt, Eric LU ; Lind-Halldén, Christina LU ; Ljung, Rolf LU orcid ; Astermark, Jan LU and Halldén, Christer LU (2020) In Journal of Thrombosis and Haemostasis 18(5). p.1039-1049
Abstract

BACKGROUND: Inversions involving intron 22 (Inv22) of F8 are detected in approximately 45% of all severe hemophilia A patients. Diagnosis is complicated by the large size of the ~9.5 kb int22h repeated sequence which generates the inversions. Methods such as long-range PCR and inverse-shifting PCR are currently used diagnostically, but suffer from low PCR efficiencies and are difficult to standardize.

OBJECTIVES: To design and validate a sensitive and robust assay for the detection of F8 int22h inversions.

METHODS: Digital droplet PCR using mile-post assays was used to investigate archival DNA samples.

RESULTS: The detection of linkage as a function of physical distance between loci was investigated using an anchor... (More)

BACKGROUND: Inversions involving intron 22 (Inv22) of F8 are detected in approximately 45% of all severe hemophilia A patients. Diagnosis is complicated by the large size of the ~9.5 kb int22h repeated sequence which generates the inversions. Methods such as long-range PCR and inverse-shifting PCR are currently used diagnostically, but suffer from low PCR efficiencies and are difficult to standardize.

OBJECTIVES: To design and validate a sensitive and robust assay for the detection of F8 int22h inversions.

METHODS: Digital droplet PCR using mile-post assays was used to investigate archival DNA samples.

RESULTS: The detection of linkage as a function of physical distance between loci was investigated using an anchor locus and mile-post loci located at 1, 6, 12 and 15 kb distances from the anchor locus. The proportion of linked molecules decreased with increasing distance between loci and showed 30-40% linked molecules for loci 12-15 kb apart. Mile-post assays specific for wild type and Inv22 type 1 and 2 chromosomes were then designed and optimized. All three assays showed high specificities and sensitivities, with coefficients of variation < 5% for all assays. Analysis of 106 patients and 20 carrier mothers showed complete concordance with previously known mutation status. The analysis demonstrated the robustness of the assays versus input DNA concentration (6 ng and higher) and level of fragmentation.

CONCLUSIONS: Digital droplet PCR and mile-post assays can be used to detect F8 int22h inversions. The assay systems are technically simple to perform, highly efficient and robust.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Thrombosis and Haemostasis
volume
18
issue
5
pages
11 pages
publisher
Wiley-Blackwell
external identifiers
  • pmid:32031725
  • scopus:85083057759
ISSN
1538-7933
DOI
10.1111/jth.14760
language
English
LU publication?
yes
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This article is protected by copyright. All rights reserved.
id
ee177b99-ae75-4da7-8901-1380498881a4
date added to LUP
2020-02-13 16:26:21
date last changed
2024-05-15 06:39:55
@article{ee177b99-ae75-4da7-8901-1380498881a4,
  abstract     = {{<p>BACKGROUND: Inversions involving intron 22 (Inv22) of F8 are detected in approximately 45% of all severe hemophilia A patients. Diagnosis is complicated by the large size of the ~9.5 kb int22h repeated sequence which generates the inversions. Methods such as long-range PCR and inverse-shifting PCR are currently used diagnostically, but suffer from low PCR efficiencies and are difficult to standardize.</p><p>OBJECTIVES: To design and validate a sensitive and robust assay for the detection of F8 int22h inversions.</p><p>METHODS: Digital droplet PCR using mile-post assays was used to investigate archival DNA samples.</p><p>RESULTS: The detection of linkage as a function of physical distance between loci was investigated using an anchor locus and mile-post loci located at 1, 6, 12 and 15 kb distances from the anchor locus. The proportion of linked molecules decreased with increasing distance between loci and showed 30-40% linked molecules for loci 12-15 kb apart. Mile-post assays specific for wild type and Inv22 type 1 and 2 chromosomes were then designed and optimized. All three assays showed high specificities and sensitivities, with coefficients of variation &lt; 5% for all assays. Analysis of 106 patients and 20 carrier mothers showed complete concordance with previously known mutation status. The analysis demonstrated the robustness of the assays versus input DNA concentration (6 ng and higher) and level of fragmentation.</p><p>CONCLUSIONS: Digital droplet PCR and mile-post assays can be used to detect F8 int22h inversions. The assay systems are technically simple to perform, highly efficient and robust.</p>}},
  author       = {{Manderstedt, Eric and Lind-Halldén, Christina and Ljung, Rolf and Astermark, Jan and Halldén, Christer}},
  issn         = {{1538-7933}},
  language     = {{eng}},
  number       = {{5}},
  pages        = {{1039--1049}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Journal of Thrombosis and Haemostasis}},
  title        = {{Detection of F8 int22h inversions using digital droplet PCR and mile-post assays}},
  url          = {{http://dx.doi.org/10.1111/jth.14760}},
  doi          = {{10.1111/jth.14760}},
  volume       = {{18}},
  year         = {{2020}},
}