trisomy

American  

[trahy-soh-mee] / ˈtraɪ soʊ mi /

noun

Pathology.

1. an abnormality characterized by the presence of an additional chromosome to the normal diploid number.

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trisomy British  

/ traɪˈsəʊmɪk, ˈtraɪsəʊmɪ /

noun

1. the condition of having one chromosome of the set represented three times in an otherwise diploid organism, cell, etc. Trisomy of chromosome 21 results in Down's syndrome

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trisomy Scientific  

/ trī-sō′mē,trī′sō′- /

1. The condition of having three copies of a given chromosome in each body cell rather than the normal number of two.

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Other Word Forms

• trisomic adjective

Etymology

Origin of trisomy

First recorded in 1925–30; tri- + -some ³ + -y ³

Example Sentences

Down syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21, also known as trisomy 21.

From Science Daily • Feb. 27, 2024

“You can’t say, ‘Oh, this change is there, so it’s trisomy 21,’” said Dr. Julia Gresky, an anthropologist at the German Archaeological Institute in Berlin who was not involved in the new study.

From New York Times • Feb. 20, 2024

But tests confirmed late last month that the baby she was carrying had a condition called trisomy 18, an extra chromosome that made it likely the baby would die in utero or shortly after birth.

From Seattle Times • Dec. 12, 2023

Carrying a pregnancy with trisomy 18 to term is associated with increased risks of gestational diabetes, preterm delivery and cesarean section.

From Salon • Dec. 12, 2023

Kate Cox, who is 20 weeks pregnant with her third child, learned that her child had full trisomy 18, a genetic condition that is almost always fatal in utero or the first year after birth.

From Slate • Dec. 8, 2023