karüotüüping

Karüotüüping, also known as karyotyping, is a laboratory test that examines the number and appearance of chromosomes in the cells of an organism. Chromosomes are thread-like structures found in the nucleus of cells that carry genetic information. Humans typically have 23 pairs of chromosomes, with 22 pairs of autosomes and one pair of sex chromosomes (XX for females and XY for males).

The process of karüotüüping involves obtaining a sample of cells, usually from blood, but can also be from amniotic fluid, bone marrow, or skin. These cells are then cultured in a laboratory to encourage them to divide. During cell division, specifically metaphase, the chromosomes become condensed and visible under a microscope. The chromosomes are then stained and photographed. A cytogeneticist arranges these photographs into a karyotype, which is a systematic display of the chromosomes ordered by size and shape.

Karüotüüping is a valuable diagnostic tool used to identify chromosomal abnormalities. These abnormalities can include changes in chromosome number, such as aneuploidy (e.g., Down syndrome, where there is an extra copy of chromosome 21) or polyploidy (an extra set of chromosomes). It can also detect structural abnormalities, such as deletions, duplications, translocations (where parts of chromosomes are exchanged), and inversions. These chromosomal alterations can lead to various genetic disorders, developmental delays, intellectual disabilities, and congenital anomalies. Karüotüüping is often performed prenatally to screen for potential genetic conditions in a fetus or after birth when a genetic disorder is suspected.