| 1. |
- Halldén, Christer, et al.
(author)
-
Origin of Swedish hemophilia A mutations
- 2012
-
In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 10:12, s. 2503-2511
-
Journal article (peer-reviewed)abstract
- Background: Hemophilia A (HA) has a high level of variation within the disease class, with more than 1000 mutations being listed in the HAMSTeRS database. At the same time a number of F8 mutations are present in specific populations at high frequencies. Objectives: The simultaneous presence of large numbers of rare mutations and a small number of high-frequency mutations raises questions about the origins of HA mutations. The present study was aimed at describing the origins of HA mutations in the complete Swedish population. The primary issue was to determine what proportion of identical mutations are identical by descent (IBD) and what proportion are attributable to recurrent mutation events. The age of IBD mutations was also determined. Patients/Methods: In Sweden, the care of HA is centralized, and the Swedish HA population consists of 750 patients from > 300 families (35% severe, 15% moderate, and 50% mild). Identical haplotypes were defined by single-nucleotide polymorphism and microsatellite haplotyping, and the ages of the mutations were estimated with estiage. Results: Among 212 presumably unrelated patients with substitution mutations, 97 (46%) had mutations in common with other patients. Haplotyping of the 97 patients showed that 47 had IBD mutations (22%) with estimated ages of between two and 35 generations. The frequency of mild disease increased with an increasing number of patients sharing the mutations. Conclusions: A majority of the IBD mutations are mild and have age estimates of a few hundred years, but some could date back to the Middle Ages.
|
|
| 2. |
- Halldén, Christer, et al.
(author)
-
Origin of Swedish hemophilia B mutations
- 2013
-
In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 11:11, s. 2001-2008
-
Journal article (peer-reviewed)abstract
- Background More than 1100 mutations that cause hemophilia B (HB) have been identified. At the same time, specific F9 mutations are present at high frequencies in certain populations, which raise questions about the origin of HB mutations. ObjectivesTo describe the mutation spectrum of all HB families in Sweden and investigate if mutations appearing in several families are due to independent recurrent mutations (RMs) or to a common mutation event (i.e. are identical by descent (IBD)). Patients/MethodsThe registered Swedish HB population consists of patients from 86 families. Mutations were identified by resequencing and identical haplotypes were defined using 74 markers and a control population of 285 individuals. The ages of IBD mutations were estimated using ESTIAGE. ResultsOut of 77 presumably unrelated patients with substitution mutations, 47 patients (61%) had mutations in common with other patients. Haplotyping of the 47 patients showed that 24 patients had IBD mutations (51%) with estimated ages of between two and 23 generations. A majority of these patients had mild disease. Eight of the 15 mutations observed in more than one family were C>T transitions in CpG sites and all eight were RMs. ConclusionsThe association of IBD mutations with a mild phenotype is similar to what has been previously observed in hemophilia A. Noteworthy features of the mutations that are common to more than one family are the equal proportions of patients with RM and IBD mutations and the correlation between the occurrence of RMs and C>T transitions at CpG sites.
|
|
| 3. |
- Manderstedt, Eric, et al.
(author)
-
Detection of F8 int22h inversions using digital droplet PCR and mile-post assays
- 2020
-
In: Journal of Thrombosis and Haemostasis. - : Wiley-Blackwell Publishing Ltd. - 1538-7933 .- 1538-7836. ; 8:5, s. 1039-1049
-
Journal article (peer-reviewed)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 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.
|
|
| 4. |
- Manderstedt, Eric, et al.
(author)
-
Droplet digital PCR and mile-post analysis for the detection of F8 int1h inversions
- 2021
-
In: Journal of Thrombosis and Haemostasis. - : Wiley-Blackwell Publishing Ltd. - 1538-7933 .- 1538-7836. ; 19:3, s. 732-737
-
Journal article (peer-reviewed)abstract
- BACKGROUND: F8 int1h inversions (Inv1) are detected in 1-2% of severe hemophilia A (HA) patients. Long-range polymerase chain reaction (PCR) and inverse-shifting PCR have been used to diagnose these inversions. OBJECTIVES: To design and validate a sensitive and robust assay for detection of F8 Inv1 inversions. METHODS: Archival DNA samples were investigated using mile-post assays and droplet digital PCR. RESULTS: Mile-post assays for Inv1 showing high specificities and sensitivities were designed and optimized. Analysis of four patients, two carrier mothers and 40 healthy controls showed concordance with known mutation status with one exception. One patient had a duplication involving exons 2-22 of the F8 gene instead of an Inv1 mutation. DNA mixtures with different proportions of wild type and Inv1 DNA correlated well with the observed relative linkage for both wild type and Inv1 assays and estimated the limit of detection of these assays to 2% of the rare chromosome. CONCLUSIONS: The mile-post strategy has several inherent control systems. The absolute counting of target molecules by both assays enables determination of template quantity, detection of copy number variants and rare variants occurring in primer and probe annealing sites and estimation of DNA integrity through the observed linkage. The presented Inv1 mile-post analysis offers sensitive and robust detection and quantification of the F8 int1h inversions and other rearrangements involving intron 1 in patients and their mothers.
|
|
| 5. |
|
|
| 6. |
- Manderstedt, Eric, et al.
(author)
-
Thrombomodulin (THBD) gene variants and thrombotic risk in a population-based cohort study
- 2022
-
In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 20:4, s. 929-935
-
Journal article (peer-reviewed)abstract
- Background: The protein C anticoagulant system plays a key role in maintaining the hemostatic balance. Although several studies have identified thrombomodulin gene (THBD) variants among venous thromboembolism (VTE) patients, the role of THBD in relation to VTE in humans remains to be clarified. Objectives: This study aimed to determine the thrombotic risk of rare and common THBD variants in a large population-based cohort of middle-aged and older adults. Patients/Methods: The exome sequence of THBD was analyzed for qualifying variants in 28,794 subjects (born 1923–1950, 60% women), who participated in the Malmö Diet and Cancer study (1991–1996). Patients were followed from baseline until the first event of VTE, death, or 2018. Qualifying variants were defined as loss-of-function or non-benign (PolyPhen-2) missense variants with minor allele frequency <0.1%. Results: The single common coding variant rs1042579 was not associated with incident VTE. Sixteen rare variants were classified as qualifying and included in collapsing analysis. Seven individuals with VTE compared to 24 individuals without VTE carried one qualifying variant. Cox multivariate regression analysis adjusted for age, sex, body mass index, systolic blood pressure, smoking and alcohol consumption, rs6025, rs1799963, and the top two eigenvectors from a principal components analysis showed a hazard ratio of 3.0 (95% confidence interval 1.4–6.3) for the rare qualifying variants. The distributions of qualifying variants in THBD showed a difference for individuals with and without incident VTE indicating a possible position effect. Conclusions: Rare qualifying THBD variants were associated with VTE, suggesting that rare variants in THBD contribute to development of VTE.
|
|
| 7. |
- Manderstedt, Eric, et al.
(author)
-
Thrombotic risk determined by rare and common SERPINA1 variants in a population-based cohort study
- 2022
-
In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 20:6
-
Journal article (peer-reviewed)abstract
- Background: Severe alpha-1-antitrypsin deficiency (AATD), phenotype PiZZ, was associated with venous thromboembolism (VTE) in a case-control study. Objectives: This study aimed to determine the genetic variation in the SERPINA1 gene and a possible thrombotic risk of these variants in a population-based cohort study. Patients/Methods: The coding sequence of SERPINA1 was analyzed for the Z (rs28929474), S (rs17580), and other qualifying variants in 28,794 subjects without previous VTE (born 1923–1950, 60% women), who participated in the Malmö Diet and Cancer study (1991–1996). Individuals were followed from baseline until the first event of VTE, death, or 2018. Results: Resequencing the coding sequence of SERPINA1 identified 84 variants in the total study population, 21 synonymous, 62 missense, and 1 loss-of-function variant. Kaplan-Meier analysis showed that homozygosity for the Z allele increased the risk of VTE whereas heterozygosity showed no effect. The S (rs17580) variant was not associated with VTE. Thirty-one rare variants were qualifying and included in collapsing analysis using the following selection criteria, loss of function, in frame deletion or non-benign (PolyPhen-2) missense variants with minor allele frequency (MAF)
|
|
