1. (noun) chrosomal abnormality in which there is one more than the normal number of chromosomes in a cell

• chromosomal aberration
• chromosomal anomaly
• chromosonal disorder
• chrosomal abnormality

1. (noun) chrosomal abnormality in which there is one more than the normal number of chromosomes in a cell

• down syndrome
• down's syndrome
• mongolianism
• mongolism
• trisomy 21