What kind of sequence modification is notable in the BRCA1 mutation 6174delT?

The BRCA1 mutation 6174delT refers to a specific mutation where a thymine (T) nucleotide is deleted from the BRCA1 gene sequence. This type of alteration is classified as a deletion because it results in the removal of one nucleotide from the overall sequence. Deletions can lead to frameshift mutations, which may disrupt the reading frame of the gene, potentially resulting in a nonfunctional protein.

In the context of genetic mutations, insertions would involve adding one or more nucleotides into the sequence, substitutions would mean replacing one nucleotide with another, and amplifications refer to increases in the number of copies of a particular DNA segment. Given that 6174delT specifically involves the loss of a nucleotide, it clearly aligns with the definition of a deletion. Therefore, it is appropriate to identify this mutation as a notable deletion within the BRCA1 gene.