What Are Chromosome Disorders?
Chromosome changes can be inherited from a parent or can happen by chance for the first time in a baby (de novo). An error called nondisjunction causes chromosomes to be separated and distributed unequally into new cells. As a result, some cells have too many chromosomes and other cells have too few. If the original egg cell or sperm cell has too many or too few chromosomes, then all the cells in the body will have the incorrect number of chromosomes. If another cell later in development gains or loses a chromosome, then only some of the cells in the body will have the incorrect number of chromosomes.
Sources to Learn More: Chromosome Abnormalities Fact Sheet (NHGRI); Are Chromosomal Disorders Inherited? (MedlinePlus)A chromosome disorder occurs when there is a change in the number, size, or structure of the chromosomes. A numerical abnormality involves a missing or extra chromosome from the chromosome pair. A structural abnormality involves an alteration to the chromosome's structure. This change in the amount or structure of material can result in problems with growth and development.
Chromosome changes can be inherited from a parent or can happen by chance for the first time in a baby (de novo). An error called nondisjunction causes chromosomes to be separated and distributed unequally into new cells. As a result, some cells have too many chromosomes and other cells have too few. If the original egg cell or sperm cell has too many or too few chromosomes, then all the cells in the body will have the incorrect number of chromosomes. If another cell later in development gains or loses a chromosome, then only some of the cells in the body will have the incorrect number of chromosomes.
Sources to Learn More: Chromosome Abnormalities Fact Sheet (NHGRI); Are Chromosomal Disorders Inherited? (MedlinePlus)