A test done on white blood cells, bone marrow, or skin cells that have been prepared and chemically treated, for detection of sex identity and various genetic diseases, such as Down syndrome, in the fetus, child, or adult.
The examination of chromosomes in cells, known as chromosome analysis, is conducted to determine the presence or nature of a chromosomal abnormality. This study helps identify and understand the specific characteristics of the abnormality in question.
Certain pregnancies carry a higher-than-average risk of the baby having a chromosomal abnormality. Factors that contribute to this increased risk include advanced maternal age, a previous child with a chromosomal defect, or the presence of a defect or rearrangement in either the mother’s or the father’s chromosomes. However, in many cases, no identifiable risk factors are present. As a result, preliminary blood tests are offered to all pregnant women to identify those at a higher risk of fetal abnormality. If the fetus is determined to be at high risk, a sample of cells is taken for chromosome analysis. In the event of a significant abnormality, such as Down’s syndrome, parents will be presented with the option of terminating the pregnancy, accompanied by genetic counseling to evaluate the risk of future pregnancies being affected.
Chromosome analysis is also performed in cases of unexplained stillbirth or when a baby is born with physical abnormalities that indicate the possibility of a chromosomal defect, such as Turner’s syndrome. This analysis aims to identify and understand any underlying chromosomal abnormalities that may be contributing to the condition.
The examination of sex chromosomes can be conducted to determine the chromosomal sex of a child with ambiguous genital appearance, to confirm or exclude the presence of chromosomal abnormalities, or to investigate issues of infertility. This analysis provides valuable insights into the underlying chromosomal factors associated with these conditions.
Fetal cells for analysis can be obtained through procedures such as amniocentesis or chorionic villus sampling. For chromosome analysis in children and adults, white blood cells are typically collected from a blood sample. These methods enable the examination of chromosomal composition and aid in the diagnosis and understanding of various genetic conditions.