Patient's question:
Problem Description: I want to get pregnant, need to check chromosomes, please ask what chromosomes are?Doctor's answer:
Hello, chromosomes are the carriers of genetic material and are the forms in which deoxyribonucleic acid (DNA) and nucleoproteins appear during cell division. In normal individuals, the number of somatic chromosomes is 46, and they have a certain morphology and structure. Abnormalities in the morphology, structure, or number of chromosomes are known as chromosomal abnormalities, and diseases caused by chromosomal abnormalities are called chromosomal diseases. Over 100 types of chromosomal diseases have been discovered so far. Chromosomal diseases can often cause miscarriage, Down syndrome, congenital multiple malformations, and tumors in clinical practice. The incidence of chromosomal abnormalities is not uncommon, reaching 0.5%-0.7% in the general newborn population. If we calculate based on the average of 3,000 newborn births annually in our hospital, there may be 15-20 cases of chromosomal abnormalities. During early spontaneous abortion, about 50%-60% are caused by chromosomal abnormalities. Common causes of chromosomal abnormalities include ionizing radiation, exposure to chemical substances, microbial infections, and genetics. The purpose of clinical chromosome testing is to detect chromosomal abnormalities and diagnose diseases caused by them. Chromosome testing involves culturing peripheral blood with cell growth stimulant phytohemagglutinin (PHA) at 37°C for 72 hours to obtain a large number of dividing cells. Then, colchicine is added to arrest the dividing cells in metaphase for chromosome observation. The cells are then treated with hypotonic solution to reduce interchromosomal entanglement and overlap, and finally fixed on slides using methanol and glacial acetic acid for microscopic observation of chromosome structure and number. A normal male's karyotype consists of 44 autosomes plus 2 sex chromosomes, X and Y, which are often represented as 46,XY in test reports. A normal female has the same autosomes as males but 2 X sex chromosomes, commonly represented as 46,XX. The "46" indicates the total number of chromosomes, and any number greater than or less than 46 is considered a chromosomal number abnormality. A missing sex chromosome is often denoted as "O." Each human cell contains 23 pairs of chromosomes, including 22 pairs of autosomes and one pair of sex chromosomes. The sex chromosomes include the X and Y chromosomes. An embryo with a pair of X chromosomes develops into a female, while one with one X chromosome and one Y chromosome develops into a male. Thus, for females, the normal sex chromosome composition is XX, and for males, it is XY. This means that all ova produced by female cells during meiosis contain one X chromosome. In males, half of the sperm contain an X chromosome, while the other half contain a Y chromosome.