Neonatal/Paediatric Genetic Tests

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.

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).

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.

Specific Microdeletion Probes

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.