Analysing the Human Genome: providing breadth and depth
Diagnostic Genetics comprises three inter-related divisions of cytogenetics, molecular haematology and molecular genetics. These divisions allow us to provide an holistic approach to resolve clinical diagnoses with a genetic component using state-of-the-art technology. We analyse pre and post-natal samples, providing predictive testing, and confirmation of a clinical diagnosis in the case of symptomatic individuals. Our portfolio of tests is constantly being upgraded with a view to reducing turnaround times and enhancing our tests to take into account new approaches and international clinical and research data.
Linkages with nearby Universities in Auckland enable Diagnostic Genetics to be connected to the best technologies and approaches to improve patient care.
- For more detailed information on our genetic services please see our test guide page (external link)
- Diagnostic Genetics request form can be downloaded here (external link)
Chromosome preparations are made from dividing cells, which are at or near the metaphase stage of the mitotic cycle. The techniques used in the Cytogenetic laboratory all aim to produce a maximum number of cells undergoing mitosis. Samples are typically grown in culture media for a number of days or weeks. When a cell culture is ready to be harvested its growth is arrested by the addition of colcemid. Colcemid halts the cell cycle at metaphase where the nuclear DNA is organised into discrete chromosomes. Metaphase chromosomes are fixed onto microscope slides and are analysed by our cytogeneticists. The analysis is called a karyotype and it describes the chromosomal makeup (constitutional or acquired) of the individual from whom the tissue originated.
The Molecular Genetics Laboratory based in LabPLUS, Auckland City Hospital was established in 1994. The laboratory at present has eight staff members, performing in excess of 1500 tests per annum.
Techniques currently employed at the Molecular Genetics Laboratory include:
- Targeted mutation analysis via direct DNA sequencing.
- Gene-based sequencing and multi-exon mutation screening using a robotic interface and automated identification of variants.
- Multiplex ligation-dependent probe amplification strategies for the detection of deletion and duplication events, and methylation analysis.
- The recent development of whole genome and targeted genome oligo-based arrays using Affymetrix and Agilent platforms.
- LOH and UPD studies using fluorescence-based microstallite analysis, and Affymetrix arrays.
- Trinucleotide repeat expansion analysis using the detection of fluorescently labeled amplicons separated by capillary electrophoresis. This approach has recently been upgraded to incorporate allele specific ladders for the more accurate sizing of amplicons.
Molecular Genetics Section Leader Pippa Dryland
Molecular Haematology provides specialised regional, and in some cases national, services related to the diagnosis, classification and management of a spectrum of malignant haematological disorders and inherited gene defects.
The DNA diagnostic laboratory focuses on the molecular analysis of a variety of haematological disorders:
- Molecular and genetic studies of haematological malignancies, including detection of minimal residual disease,
- Prenatal and carrier services for the inherited coagulation and haemoglobin disorders,
- Molecular analysis of prothrombotic risk factors and,
- Molecular analysis of haemochromatosis.
Specimens include peripheral blood, bone marrow, chorionic villi or amniotic fluid cells. Please see the relevant test information for specimen requirements. Techniques used include Southern blot, PCR, RT-PCR, Quantitative PCR, Fluorescent allele discrimination, DNA sequencing, RFLP, (CA)n and direct mutation analysis.
Molecular Haematology Section Leader Nikhil Ghallyan