Trisomy 22

Trisomy 22 is a chromosomal disorder in which three copies of chromosome 22 are present in the cells of the body instead of the usual two. The extra copy may be present in all cells or in only some of them, and an individual may instead carry a variation of chromosome 22. The source describes it as a frequent cause of spontaneous abortion during the first trimester of pregnancy, so most affected pregnancies end early. Progression into the second trimester and live birth are described as rare. The condition is recorded here as a documented chromosomal abnormality, not as medical advice.