Advanced
Technical
In the Industry Vocabulary Test
aneuploidy
Pronunciation: AN-yoo-ploy-dee
Abnormal number of chromosomes, either missing or extra chromosomes.
Full Definition
A chromosomal condition characterized by having an abnormal number of chromosomes, typically one chromosome too few (monosomy) or one too many (trisomy). Common aneuploidies detected in prenatal screening include trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome). Most aneuploidies result from nondisjunction during meiosis and risk increases with maternal age, particularly for trisomy 21.
Usage
Usage note: Distinguish from structural chromosomal abnormalities in genetic counseling contexts.
In Context
- "Screening detected fetal aneuploidy requiring diagnostic confirmation." — genetic report
- "Advanced maternal age increases aneuploidy risk, particularly trisomy 21." — patient education material
Also known as
chromosomal aneuploidy
Contrasted with
euploidy
Don't confuse with
polyploidy
structural chromosomal abnormality