Cytogenetik

Cytogenetik, or cytogenetics, is the branch of genetics that studies chromosomes—their number, structure, and behavior—and how chromosomal changes influence development and disease. The field combines cytology and molecular biology to analyze chromosomes in cells, using traditional karyotyping and modern genome-wide approaches. It covers constitutional cytogenetics, focusing on inherited chromosome variations, and somatic cytogenetics, addressing acquired changes in diseases such as cancer.

Techniques commonly used include karyotyping with G-banding to detect numerical and large structural abnormalities, and fluorescence in situ hybridization (FISH) for targeted detection of specific regions. Chromosomal microarray analysis (CMA) detects submicroscopic copy-number changes and more comprehensive approaches use sequencing and advanced imaging to identify structural variants.

Applications span clinical diagnostics and research. Prenatal cytogenetics screens for aneuploidies and major rearrangements, informing pregnancy management. In postnatal cases, cytogenetics assists in diagnosing constitutional disorders and guiding treatment plans. In oncology, cancer cytogenetics identifies characteristic chromosomal translocations and deletions that influence prognosis and therapy, such as leukemias and lymphomas. The field also contributes to infertility workups, developmental disorder investigations, and comparative genomic studies.

History highlights include early chromosome microscopy, the determination of the human chromosome number in the 1950s, the advent of banding techniques in the 1970s, the introduction of FISH in the 1980s, and genome-wide approaches becoming routine in the 1990s and 2000s.