A condition in which an extra copy of a chromosome is present in the cell nuclei, causing developmental abnormalities.
- ‘If the proband has trisomy 21, the likelihood of a trisomy 21 pregnancy is minimally increased for family members other than the parents.’
- ‘Both monosomy and trisomy of specific chromosomes are associated with developmental defects and cancer risk.’
- ‘The aneuploid embryos detected in the progeny from this cross include trisomies and UPDs of chromosomes 7 and 18.’
- ‘A common type of chromosomal abnormality is called a trisomy.’
- ‘First-trimester screening also can help detect other chromosomal abnormalities such as trisomy 18.’
1930s: from tri- three + -some.