Use in clinical context
Changes that can make alternate versions of genes include the swapping, deleting or adding of an individual base, the duplication of a number of bases or deletion of whole regions. Some, but not all, alleles have functional implications. A genetic test result can reveal if an individual carries alternate forms of a gene and if this allele has clinical significance. In some cases, only one copy of the alternate form of the gene is needed for the condition to present. In others, both copies must be the alternate form for the condition to present.