Microarray analysis (Array CGH) represents the cutting edge of genetic analysis. This is a molecular test requiring patient DNA, capable of detecting very small imbalances (gains and losses), in the kilobase range compared to 5-10 megabases in conventional karyotyping.
Array CGH analysis is recommended as the ‘first tier’ test for children with congenital abnormalities, intellectual problems, developmental delay and/or dysmorphism.
Although DNA-based tests are becoming increasingly important in the diagnosis of chromosome disorders, conventional chromosome analysis (karyotyping) is still the mainstay diagnostic test for a range of chromosome rearrangements and conditions.
The postnatal section offers karyotype analysis for, couples experiencing recurrent miscarriage and implantation failure, the detection of autosomal trisomies (e.g. Down syndrome) and the diagnosis of sex chromosome syndromes (e.g. Turner and Klinefelter syndromes).
FISH testing can serve as an adjunct for the further delineation of chromosome abnormalities detected by karyotyping and Array CGH or as a standalone test for the diagnosis of specific microdeletion syndromes, for example, Williams and DiGeorge syndrome. Rapid FISH testing and QF-PCR is also available for the diagnosis of the autosomal trisomes in newborns.
The chromosome breakage disorders are a diverse set of rare genetic conditions (usually autosomal recessive) often characterised by a predisposition to malignancy and associated with chromosome breakage or fragility. The genetic defect causes genomic instability or an inability to repair DNA damage.
Test |
Cost NZD* |
Sample Requirements |
Current TAT |
---|---|---|---|
Blood karyotype | $373 | Paediatric (0-6mths): 1-2 ml whole blood in a lithium heparin (LH) tube (green top) >6mths: 2-5 ml whole blood in a LH tube |
4 days for urgent samples. 5 days for routine samples |
Array CGH | $693 (proband) $347 (parental studies) |
Paediatric (0-6mths): 1-2 ml whole blood in both LH & EDTA (purple top) tubes >6mths: 2-5 ml whole blood in LH and EDTA tubes |
4 days for urgent samples. 9 days for routine samples |
FISH | $533 | Paediatric (0-6mths): 1-2 ml whole blood in a LH tube >6mths: 2-5 ml whole blood in a LH tube |
3 days |
**Chromosome instability/breakage disorders | $1225 | At least 6 ml whole blood in a LH tube | 8 days |
* No direct charge for the Central Region DHBs covered by the Crown Funding Agreement
** Please contact the laboratory if chromosome breakage/instability testing is required