Molecular
diagnosis in laboratory medicine
Molecular
biology has a vital role to play in the diagnosis and management
of many disorders, and the number of applications in laboratory
medicine is constantly increasing. Rapid genetic techniques
are superseding many existing conventional tests, with marked
improvements to the service provided to patients. Genetic
analysis provides important information that may not be obtainable
by other methods including carrier and prenatal diagnosis
in haemophilia and other inherited bleeding disorders, testing
for inherited risk factors for thrombosis, molecular diagnosis
and monitoring in leukaemia, and genetic family studies of
inherited haemoglobin disorders such as thalassaemia. There
are also many applications for molecular biology techniques
in the diagnosis and treatment of infection, including testing
for hepatitis and other viruses, monitoring the impact of
new vaccines, such as meningitis vaccine, and evaluating the
response to HIV therapy.
Current
molecular diagnostic service provision in the MDC
•
Inherited bleeding disorders (haemophilia and von
Willebrand disease). A comprehensive
genetic carrier and prenatal diagnostic service for the north-west
of England. Full gene mutation screening has been developed
and introduced for these disorders since the MDC became operational.
This approach to diagnosis has superseded the previous gene-linkage
based service. The laboratory is a member of the UK Haemophilia
Centre Doctors’ Organisation (UKHCDO) Genetics Laboratory
Network, which was established in 2002 to provide a national
network to ensure a robust and high quality genetic diagnostic
service across the UK for patients and families with inherited
bleeding disorders.
•
Venous thromboembolism (VTE). A
diagnostic service provision for the north-west of England
to identify genetic risk factors for VTE. The automation of
PCR based assays using the equipment available in the MDC
has greatly enhanced this “high-throughput” service
provision.
•
Haematological malignancies. A
comprehensive molecular diagnostic service provision was introduced
during 2003. Molecular diagnosis is available to clinicians
across the north-west for acute myeloid leukaemia, acute lymphocytic
leukaemia, chronic myeloid leukaemia and lymphoma. Molecular
monitoring is provided in bone marrow transplantation.
•
Hereditary haemochromatosis. A
genetic diagnostic service for the north-west of England.
The PCR-based methodology used has been automated using the
equipment available in the MDC.
•
Genotyping of cholinesterase variants. This
new service provision was introduced in 2003 to expand and
complement the current diagnostic service provided by the
Department of Biochemistry at the MRI.
Planned
service development
•
Genetic carrier and prenatal diagnostic service in
thalassaemia. Method development has
been undertaken and part-time secondment of a Biomedical Scientist
from the Department of Haematology is available. Additional
funding is being sought to introduce this important development
as a diagnostic service provision for the north-west. At the
present time there is no genetic diagnostic service provision
for the haemoglobinopathies in the north-west of England.
Appropriate funding for a member of staff and to provide consumable
costs would allow this service to be introduced, and to function
as part of a genetic diagnostic network across the UK for
at risk patients and families.
Current
research activities
•
Molecular oncology. The Molecular
Oncology Group is undertaking a number of research programmes
including the molecular monitoring of minimal residual disease
in acute myeloid leukaemia (AML) as part of the MRC AML15
trial. Other projects include the study of genetic abnormalities
and the identification of prognostic markers and molecular
targets for gene therapy in leukaemia.
•
Haemostasis and thrombosis – The
current major research activity in this field is a UK national
collaborative study of the molecular pathogenesis of type
1 von Willebrand disease (VWD).
Tony Cumming
March 2004
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