Some children are born with genetic defects that are not carried by a single gene. Instead, an error in a larger part of the chromosome or even in an entire chromosome causes the disorder. Usually the error happens when the egg or sperm is forming. Having extra chromosomes or damaged chromosomes can cause disorders.
Chromosomal disorders also occur when part of a chromosome becomes damaged. For example, if a tiny portion of chromosome 5 is missing, the individual will have cri du chat (cat’s cry) syndrome. These individuals have misshapen facial features, and the infant’s cry resembles a cat’s cry.
Changes in chromosome number can lead to disorders like Down syndrome.
Chromosomal disorders also occur when part of a chromosome becomes damaged.
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