Haemophilia in Sweden – Studies on mutations and clinical implications

    Research output: ThesisDoctoral Thesis (compilation)

    Abstract

    Introduction: Haemophilia A (HA) and B (HB) are two of our most common inherited bleeding disorders and are
    due to a variety of gene mutations.
    Aims: The overall objective of the present research was to perform clinical and basic scientific studies on
    haemophilia in Sweden to further improve and individualise the care of haemophilia patients and their relatives.
    More specific aims were: to study trends and changes for prenatal diagnosis (PND) of haemophilia (paper I); to
    describe the mutation spectrum of HB and its origin in terms of the mutations being recurrent mutations or
    identical by descent (IBD) (paper II); to analyse the mutation profile in HB highlighting unique mutations and
    inhibitor development alongside genotype-phenotype associations (paper III); and to define the origin of mutations
    of sporadic severe cases of HA.
    Methods and results: Through semi-structured interviews and PND-registry data, 90 PND performed by 54 women
    during 1977–2013 were found. There were 27/90 haemophilia-affected foetuses of which 16 went to termination
    and 11 were born (during 2000–2013). PND was used in 27/55 cases for mental preparation (paper I). Mutation
    analysis found 47/77 patients to share mutations, and haplotype analysis found (51%) (24/47) to be IBD, the
    majority of these were mild forms (paper II). Mutation and haplotype analysis among 113 families (each
    represented by one patient) identified 32% ‘null mutations’ and 19% inhibitor among the severely affected
    families, whereas the frequency of unique mutations was at least 65% (paper III). In 40/45 sporadic families the
    mutation occurred within the last two generations and in 82% (23/28) the mother was hitherto an unknown carrier.
    Conclusions: PND is increasingly used as a psychological preparation for having a child with haemophilia (paper
    I). Mild forms of haemophilia associated with IBD have estimated ages of mutations of between two and 23
    generations (paper II). A high frequency of unique mutations was found. The high number of inhibitor families is
    most likely caused by many ‘null mutations’ (paper III). Due to the young age of mutations, this indicates relatives
    having a low carrier risk (paper IV).
    Original languageEnglish
    QualificationDoctor
    Awarding Institution
    Supervisors/Advisors
    • Ljung, Rolf, Supervisor
    • Tedgård, Ulf, Supervisor
    Award date2015 Oct 16
    Publisher
    ISBN (Print)978-91-7619-182-8
    Publication statusPublished - 2015

    Bibliographical note

    Defence details

    Date: 2015-10-16
    Time: 13:00
    Place: Kvinnoklinikens aula, Skånes universitetssjukhus Malmö

    External reviewer(s)

    Name: Lassila, Riitta
    Title: Professor
    Affiliation: Helsinki University, Finland

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    Subject classification (UKÄ)

    • Hematology
    • Pediatrics

    Free keywords

    • haemophilia
    • factor VIII
    • factor IX
    • factor 8 gene
    • factor 9 gene
    • carriers
    • prenatal diagnosis
    • mutations
    • inhibitors
    • haplotype

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