Neonatal and paediatric genetics centres around the diagnostic investigation of developmental delays, autism spectrum disorder, learning difficulties, and where there are clinical indications of congenital anomalies. As with pre-natal cytogenetics, there are a number of techniques that can be used, depending on the clinical condition under investigation. All can be performed on a blood sample.
Conventional chromosome testing is the applicable for the investigation of syndromes such as Down syndrome, Turner Syndrome and reproductive health.
Conventional cytogenetic analysis involves the analysis of the whole genome at the cellular level to detect large genomic changes and chromosomal rearrangements. This test involves culturing white blood cells to produce metaphase spreads of chromosomes, from which slides are prepared and representative cells are captured into digital images.
Test Name | Chromosomes Blood |
Clinical Indication |
For investigation of:
|
Gene(s) | Chromosomal Analysis |
Method | Conventional chromosome analysis |
Turn Around Time | 35 days |
Medicare Eligibility | 73289 |
Sample Type | Blood |
Collection Type | 10mL Lithium Heparin; For Difficult/Paediatric Collect: Min 1mL |
Special Instructions | Transport cooled or at room temperature. |
Chromosome microarray (also known as molecular karyotyping) is the gold standard for the diagnostic investigation of autism spectrum disorder, learning difficulty, developmental delay and where there are clinical indications of congenital anomalies. This is an advanced genome-wide investigation used to detect sub-microscopic detect loss and/or gain of DNA that are associated with microdeletion and microduplication syndromes but are not readily detectable by conventional karyotype and/or fluorescence in-situ hybridisation (FISH).
Test Name |
Chromosomal Microarray- Blood |
Clinical Indication |
For the first line investigation of intellectual disability, developmental delay, autism, or in the presence of at least two congenital abnormalities. |
Gene(s) |
Genome-wide |
Method |
Chromosomal Microarray |
Turn Around Time |
4 - 6 Weeks |
Medicare Eligibility |
73292- Criteria applies |
Sample Type |
Blood |
Collection Requirements |
Blood: 6ml in EDTA tube |
Special Instructions |
Request ‘Chromosomal Microarray’ on referral form. Clinical details required. |
Fluorescence in-situ hybridisation (FISH) is a targeted molecular cytogenetic technique used for the investigation of specific chromosome regions involved in the particular Syndrome. The technique binds a colour labelled DNA probe to a specific region on the patient chromosomes. As this is a targeted test it is important when requesting a FISH test to indicate the clinical condition that is being tested for.
Test Name | FISH Blood |
Clinical Indication | For neonatal diagnosis of suspected chromosomal syndromes |
Gene(s) | Chromosomes X and 21 |
Method | FISH |
Turn Around Time | 2 days |
Medicare Eligibility | 73291 |
Sample Type | Blood Paediatric Collect |
Collection Type | Min 1mL in 1 x Lithium heparin tube |
Special Instructions | No additional sample required. Test is performedwith chromosome analysis |
Specific Microdeletion Probes
Syndrome/Indication | Chromosome location | Gene |
1p36 microdeletion | 1p telomere/1p36 | Genes at 1p36 |
WOLF-HIRSCHHORN | 4p16.3 | Genes at 4p |
Cri du Chat | 5p15.2 | EGR1 |
Sotos | 5q31 | NSD1 |
Williams-Beuren | 7q11.23 | ELN |
Prader Willi | 15q11-q13 | Genes at 15q11.2-q13 |
Angelman | 15q11-q13 | Genes at 15q11.2-q14 |
Smith-Magenis | 17p11.2 | RAR1 |
Miller-Dieker | 17p13.3 | LIS1 |
Di George/VCFS | 22q11.2 | Genes at 22q11.2 |
22q microdeletion syndrome | 22q13.3 | Genes at 22q13 |
X inactivation | Xq13.2 | XIST |
Xp Yp deletions | Xp and Yp | SHOX |
Yp rearrangements | Yp11.3 | SRY |
ACRO P = Acrocentric p-arms | All sub-telomere probes | |
All chromosomes | p-arms acrocentrics | |
All chromosomes | Whole chromosome paints |
Gilbert Syndrome is characterised by jaundice due to increased levels of unconjugated plasma bilirubin. Men are at higher risk than females and usually present post-puberty. In people of northern European ancestry, cases of Gilbert Syndrome are often associated with inheriting two copies (one from each parent) of a specific mutation in the promoter region of the gene encoding the enzyme glucuronyltransferase (UGT1A1), designated UGT1A1*28 allele. UGT1A1 is a liver enzyme important for clearing conjugated bilirubin from the circulation. In general, other than the low grade elevated bilirubin levels, people with Gilbert Syndrome exhibit no other signs or symptoms.
Testing for Gilbert Syndrome may assist in differentiating the cause of isolated elevated bilirubin levels in those patients with normal test results for FBC, reticulocytes, haptoglobin and liver enzymes.
Test Name |
Gilbert’s Syndrome Genotyping |
Clinical Indication |
|
Gene(s) |
UGT1A1 (UDP-glucuronosyltransferase Family 1 Member A1) |
Method |
PCR Genotyping |
Turn Around Time |
28 days |
Medicare Eligibility |
No |
Medicare Descriptor |
N/A |
Sample Type |
Blood |
Collection Type |
10mL EDTA tube |
Special Instructions |
None |