For Patients/Families

Chromosomal abnormalities
Also called chromosomal malformations, anomalies, or defects. This refers to abnormalities in the number or organization of chromosomes. A common example is trisomy 21 or Down syndrome, in which there is an extra chromosome number 21. This extra chromosome results in a constellation of abnormalities usually recognizable at birth and consistent from one patient with Down syndrome to another.