A genetic change may also be called a “mutation,” a “variant” or a “gene change.”
Genetic changes may occur at the large-scale level (an extra chromosome – for example, in Down syndrome).
There can also be extra or missing sections of the chromosome (deletions or duplications – for example, 16p11.2 deletion/duplication), these are also called copy number variants (CNVs).
There can also be changes in the genetic code at the DNA level that affect just one gene (you may have heard of sickle cell disease or cystic fibrosis, for example).
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