Word parts
What it means
A genetic condition in which a cell carries an extra chromosome, usually because chromosomes did not separate properly during the making of an egg or sperm. Trisomy 21 is Down syndrome; trisomy 18 (Edwards syndrome) and trisomy 13 (Patau syndrome) are rarer and more severe. The risk rises with the age of the birthing parent.
For the nurse
Prenatal screening and diagnostic tests, such as chorionic villus samplingkor-ee-ON-ik VIL-us SAM-plingA prenatal test that takes a small sample of tissue from the placenta to check the baby's chromosomes and genes.Full entry and amniocentesis, can find a trisomy. Families need clear information and genetic counseling.
At a glance
| Spanish | trisomía |
|---|---|
| Also written | trisomies |
Related terms
Down syndrome
A genetic condition in which a person has a third copy of chromosome 21.
chromosome
A thread-like structure in the nucleus of a cell that carries the genes, made of tightly packed DNA.
chorionic villus sampling
A prenatal test that takes a small sample of tissue from the placenta to check the baby's chromosomes and genes.
meiosis
Cell division that makes eggs or sperm, each with half the usual number of chromosomes.