metafasekaryogrammen

A metafasekaryogram is a diagnostic tool used in cytogenetics to visualize and analyze the complete set of chromosomes from a cell during metaphase, the stage of mitosis when chromosomes are most condensed and easily identifiable. The term combines "metafase" (metaphase) with "karyogram," which refers to a photographic representation of an individual’s chromosomes arranged in pairs according to size, shape, and banding patterns.

During metaphase, chromosomes align at the cell’s equatorial plane, allowing for clear visualization under a microscope. Cells are typically harvested from peripheral blood, bone marrow, or other tissues, stimulated to divide in vitro, and treated with colchicine to arrest them in metaphase. The chromosomes are then stained with specific dyes, such as Giemsa, to produce G-banding, which creates distinct light and dark bands that aid in chromosome identification.

A karyogram is generated by photographing the metaphase chromosomes, cutting them from the image, and arranging them in a standardized order—usually from largest to smallest—with homologous pairs aligned vertically. This arrangement facilitates comparison with known chromosome banding patterns, enabling the detection of numerical or structural abnormalities, such as trisomies, deletions, translocations, or inversions.

Metafasekaryogrammen are commonly used in prenatal diagnosis to screen for chromosomal disorders like Down syndrome (trisomy 21), as well as in the diagnosis of genetic conditions in newborns and adults. They are also applied in oncology to identify chromosomal alterations associated with cancers, such as chronic myeloid leukemia (Philadelphia chromosome) or lymphoma. Advances in digital imaging and automated analysis have improved the accuracy and efficiency of karyotyping, reducing human error in chromosome interpretation.