Fluorescence in-situ hybridisation (FISH)

what is FISH?

molecular cytogenetic technique used to detect and localise specific DNA sequences

what is the fundamental principle of FISH?

Use of fluorescently labelled DNA probes
Binding to complementary target sequences
Visualization of genetic loci and chromosomal abnormalities

what is the importance of FISH?

precise detection and characterisation of genetic abnormalities

association with congenital and acquired diseases

what are the clinical diagnostics of FISH?

Identification of chromosomal aberrations in prenatal and postnatal genetic testing
Diagnosis and prognosis of genetic disorders

what are the types of probes?

Whole chromosome painting probes
Locus-specific probes
Centromere-specific probes
Utilized in various FISH applications for visualizing specific genetic loci or chromosomal regions.

what is the hybridization process>

denaturation of target DNA

probe binding, annealing and incubation under controlled conditions

what are the detection methods?

Direct detection using fluorescently labelled probes.
Indirect detection through amplification techniques
Enhances signal and improves detection sensitivity.

what is the equipment used for imaging and microscopy techniques for FISH analysis and the functionality of it?

High-resolution fluorescence microscopes
Appropriate filter sets
Imaging software

Functionality - Capture fluorescent signals emitted by probes
Visualization and analysis of chromosomal or genetic abnormalities at the subcellular level

what is the genetic disease diagnosis and prognosis?

Enables detection of chromosomal abnormalities, gene deletions, or duplications
Identification of genetic aberrations related to conditions such as Down syndrome, Prader-Willi syndrome, and Angelman syndrome
Provides insights for patient management and genetic counselling

what is the prenatal screening and diagnosis?

Extensively used in prenatal screening to detect common aneuploidies in foetal cells obtained through procedures like amniocentesis and chorionic villus sampling (CVS)
Allows for timely and accurate prenatal diagnosis, aiding informed decision-making and appropriate prenatal care

what is the use of detection of chromosomal abnormalities and genetic markers in cancer?

Enables detection of specific chromosomal abnormalities, gene amplifications, deletions, and translocations associated with various types of cancer.
Visualization of genetic markers (e.g., HER2/neu amplification in breast cancer, BCR- ABL fusion in chronic myeloid leukaemia, MYC amplification in solid tumours)
Aids in cancer subtype classification, treatment stratification, prognostic evaluation

how are FISH patterns and signals interpreted?

Involves comprehending patterns and signals related to the number, size, and location of fluorescent signals corresponding to DNA probes bound to specific chromosomal or genetic loci.
Patterns include normal diploid signals, monosomy, trisomy, deletion, duplication, translocation, split signals, or other aberrations, each with distinct implications for genetic and clinical analysis.

what is the clinical significance and implications of FISH?

Contribution to accurate disease diagnosis, prognosis, and treatment decisions
Informs patient management, genetic counselling, and personalized therapeutic
interventions based on the genetic profile revealed by FISH analysis.

what are the ethical guidelines and considerations for FISH research and clinical use?

Nuremberg Code
Emphasizes voluntary consent and minimizing risks in clinical research studies.
Declaration of Helsinki
Provides ethical principles for biomedical research, emphasizing the protection of research participants.
Belmont Report
Outlines principles of respect for persons, beneficence, and justice, serving as a
foundation for ethical conduct in research practices

what is the patient confidentiality and informed consent for FISH?

Laws such as HIPAA in the USA and similar regulations in the UK ensure the protection of patients' health information and require consent for disclosure.

The principles of voluntary consent and the provision of relevant information to
patients are fundamental to the ethical conduct of FISH testing and research.

what are the future directions and research trends in FISH?

High-Resolution Imaging
Integration of super resolution imaging systems for enhanced visualization of nuclear structures and gene functions
Multiplex FISH
Advancements in probe labelling efficiency facilitating the development of multiplex FISH assays for simultaneous detection of multiple DNA or RNA sequences in single cells
Microfluidic Platforms
Use of microfluidic devices for FISH analysis, streamlining the process and offering miniaturized and automated solutions for detecting chromosome abnormalities

What are the emerging research areas and potential impact on medical science?

Personalized Medicine - Increasing demand for FISH technology in biomarker research and personalized medicine, contributing to tailored therapies in cancer and other diseases
Single-Cell Analysis - Single-molecule RNA FISH and simultaneous RNA-DNA FISH techniques opening new avenues for quantitative imaging of RNA molecules and simultaneous detection of mRNA and protein in single cells
Expanded Disease Research - FISH playing a pivotal role in detecting expanded repeats in human diseases, analysing sperm aneuploidy frequencies, and contributing to the diagnosis and tailored therapies in solid tumours