Genetic testing revealed these two mutations (hypothetically):
IVS11+6G>A and IVS11-4G＞A
Could you please explain every part of this notation, especially "+" and "-" signs.
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$\begingroup$ have you tried googling first? if not, this query yields a useful page: Nomenclature for the description of sequence variations. Quote: 88+1G>T (alternatively IVS2+1G>T) denotes the G to T substitution at nucleotide +1of intron 2, relative to the cDNA positioned between nucleotides 88 and 89 $\endgroup$– aaaaa says reinstate MonicaMay 7, 2015 at 3:24
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1 Answer
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These describe mutations (SNPs) in introns.
IVS stands for intervening sequence (which is another term for intron).
The number following IVS specifies which intron the mutation occurs in (intron 1 follows exon 1, etc).
The +n or -n, where n is an integer, gives the location of the nucleotide. +n counts 3' from the preceding exon whereas -n counts 5' from the following exon. I think that the first and last nucleotide of each exon is given position 0 such that, for example, +1 refers to the first nucleotide of the intron and -1 refers to the last.
X>Y, where X and Y are nucleotides, describe what mutation has occurred.
IVS11+6G>A means a G to A transition at position +6 of intron 11
IVS11-4G＞A means a G to A transition at position -4 of intron 11
answered May 6, 2015 at 23:07