Fluorescence in-situ hybridisation (FISH) for specific genetic syndromes

Fluorescence in-situ hybridisation (FISH) is a molecular cytogenetic technique used for the investigation of genes in specific chromosome regions. 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.

At Genomic Diagnostics, FISH is used for the rapid diagnosis of suspected genetic syndromes such as Trisomy 21 (Down syndrome) and Turner Syndrome, or others listed below.
The technique can also be used for the gender determination in the presence of ambiguous genitalia. This test can determine mosaicism, and is usually performed in conjunction with conventional cytogenetic karyotype.

Syndrome/Indication Chromosome location Test Gene
 1p36 microdeletion  1p telomere/1p36  FISH  Genes at 1p36
 WOLF-HIRSCHHORN  4p16.3  FISH  Genes at 4p
 Cri du Chat  5p15.2  FISH  EGR1
 Sotos  5q31  FISH  NSD1
 Williams-Beuren  7q11.23  FISH  ELN
 Prader Willi  15q11-q13  FISH  Genes at 15q11.2-q13 
 Angelman  15q11-q13  FISH  Genes at 15q11.2-q14 
 Smith-Magenis  17p11.2  FISH  RAR1
 Miller-Diecker  17p13.3  FISH  LIS1
 Di George/VCFS  22q11.2  FISH  Genes at 22q11.2
 22q microdeletion syndrome   22q13.3  FISH  Genes at 22q13


 Test  FISH for genetic syndromes 
Genes Targeted specific genes or chromosomes 
Disease Down syndrome features, ambiguous genitalia 
Method Dark field light microscope
Notes Clinical notes indicating the condition that is being investigated is required. This test is performed in conjunction with a conventional or molecular karyotype.
Specimen  1-2mL Lithium heparin
Turn Around Time 1-2 working days
Required Documents Physician Test Request Form
Price Medicare rebate