Study of the chromosomes in body cells to discover whether a chromosomal abnormality is present or to establish its nature. Fetal cells for analysis can be obtained in the uterus by amniocentesis or chorionic villus sampling. If a serious abnormality such as Down’s syndrome is identified, termination of the pregnancy and genetic counselling is offered. Chromosome analysis is also carried out when a baby is stillborn without an obvious cause, or is born with abnormal physical characteristics that suggest a chromosomal defect, such as Turner’s sydrome. Chromosome analysis in children and adults uses white blood cells taken from a blood sample. Analysis of the sex chromosomes may be carried out to establish the chromosomal sex of a child in cases where the genitals have an ambiguous appearance (see genitalia, ambiguous); to confirm or exclude the diagnosis of chromosomal abnormalities; or to investigate infertility.
Chromosome analysis |
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