Molecular Cytogenetic (FISH)

Molecular Cytogenetics (FISH)

When the resolution of conventional cytogenetic methods is not sufficient for the diagnosis, Molecular cytogenetic techniques used to show the presence of submicroscopic chromosomal anomalies ( microdeletion / microdublication). 

Molecular cytogenetics is a combination of cytogenetics and molecular biology which increases the resolution of cytogenetic analysis and its effectiveness in diagnosis. It involves using a variety of molecular techniques to visualize one or more specific regions of the genome or all. The basic method of molecular cytogenetics is fluorescent in situ hybridization (FISH), and with this method, submicroscopic change in a specific chromosome can be demonstrated using labeled probes. In addition, Array-CGH and Microarray analyzes, in which unbalanced copy number changes (losses and gains) in all chromosomes are shown, are among advanced Molecular Cytogenetic methods.

What are Prenatal / Postnatal FISH Applications?

Today, numerical aneuploidy analysis and structural deletion / duplication analysis can be performed from the blood sample taken from the mother with newly developed techniques such as NIPT (non-invasive prenatal test). In addition, rapid aneuploidy examinations with FISH tests from the samples  such as peripheral blood, amniocentesis, chorionvillusbiopsy (CVS), cordocentesis (CS), low evacuation material, tissue biopsy are performed for the detection and diagnosis of microdeletion syndromes such as Prader-Willi / Angelman Syndrome, Di George Syndrome, Williams Syndrome.

What are the Molecular Cytogenetic Test Indications?

• Microdeletion syndromes
• To elaborate the changes seen in routine cytogenetic examinations.
• Hematological cancers
• Genetic examinations in cancer tissue or biopsy material
• Rapid aneuploidy examination by FISH from amniotic fluid, CVS, bone marrow, peripheral blood (13, 18, 21, X and Y)
• Structural and numerical anomalies that cannot be detected in some chromosome analysis

What Should Be the Material for the Test?

• Amniotic fluid in sterile sealed syringe
• Blood, bone marrow etc. in heparin injector or heparin tube
• Paraffin embedded tumor tissue fixed on a 3-4 micron slide or in block form
• Sperm sample in sterile urine container
• Pellet containing chromosome or nucleus in the carnoyphicative

In our Molecular Cytogenetics Laboratory, following tests are applied ; 

Molecular Cytogenetic Tests

• Fast Aneuploidy (13,18,21, X, Y) FISH panel
• Microdeletion FISH analysis
• Subtelomeric FISH analysis
• FISH analysis with specific probes
• FISH analysis in hematological malignancies
• FISH analysis in solid tumors
• Sperm FISH analysis (13, 18, 21, X and Y)