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Homozygous familial hypercholesterolaemia in Vietnam: Case series, genetics and cascade testing of families

  • Thanh Huong Truong
    Affiliations
    Department of Cardiology, Hanoi Medical University, Hanoi, Vietnam

    Vietnam National Heart Institute, Bach Mai Hospital, Hanoi, Vietnam
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  • Ngoc Thanh Kim
    Correspondence
    Corresponding author. Vietnam National Heart Institute, Bach Mai Hospital, 78 Giai Phong Road, Dong Da District, Hanoi, Vietnam.
    Affiliations
    Department of Cardiology, Hanoi Medical University, Hanoi, Vietnam

    Vietnam National Heart Institute, Bach Mai Hospital, Hanoi, Vietnam
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  • Mai Ngoc Thi Nguyen
    Affiliations
    Vietnam National Heart Institute, Bach Mai Hospital, Hanoi, Vietnam
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  • Jing Pang
    Affiliations
    School of Medicine, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Australia
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  • Amanda J. Hooper
    Affiliations
    School of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Australia

    Department of Clinical Biochemistry, PathWest Laboratory Medicine WA, Royal Perth Hospital and Fiona Stanley Hospital Network, Perth, Australia

    School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Australia
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  • Gerald F. Watts
    Affiliations
    School of Medicine, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Australia

    Lipid Disorders Clinic, Cardiometabolic Services, Department of Cardiology, Royal Perth Hospital, Perth, Australia
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  • Doan Loi Do
    Affiliations
    Department of Cardiology, Hanoi Medical University, Hanoi, Vietnam

    Vietnam National Heart Institute, Bach Mai Hospital, Hanoi, Vietnam
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      Highlights

      • Familial hypercholesterolaemia (FH) is not well studied in Vietnam.
      • Homozygous and heterozygous FH are severe disorders that requires early detection and treatment, however treatment with statins, apheresis and novel therapies is a challenging healthcare gap in Vietnam.
      • Owing to large pedigrees, cascade screening in Vietnam is a highly effective method of diagnosing new cases of FH in family members once an index case has been identified.
      • A lower LDL-cholesterol thresholds should be employed in the Vietnamese population for diagnosing FH.

      Abstract

      Background and aims

      Familial hypercholesterolaemia has not been previously described in the Vietnamese population. We aimed to describe the features of patients with homozygous familial hypercholesterolaemia (hoFH) in Vietnam and the outcomes of screening family members using genetic and cholesterol testing.

      Methods

      Mutation testing by massively parallel sequencing for genes causative of FH was undertaken in five index cases presenting to a single cardiac center with a presumptive diagnosis of hoFH. Cascade testing of all available family members was subsequently undertaken. The number of new cases of FH detected and commenced on lipid-lowering treatment was evaluated.

      Results

      All five index cases had true homozygous mutations in the LDL receptor gene (LDLR). Cascade screening was undertaken in four families. 107 relatives were screened and FH was identified in 56 relatives (52%), including 3 new cases of hoFH. Only 5 FH relatives (9%) were subsequently treated owing to the adverse perceptions and comparative high cost of drug treatment, and lack of awareness of FH among patients and local doctors.

      Conclusions

      HoFH due to LDLR mutations is a severe disorder in Vietnam that needs early detection and treatment with LDL-cholesterol lowering drugs. Cascade testing of families allows effective detection of new cases of FH that may also benefit from early treatment. However, convincing patients to commence statin treatment is a challenge. Extended education and awareness programs and treatment subsidies are imperative to improve the care of patients and families suffering from FH in Vietnam.

      Keywords

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