Figure 5From: Challenges in the association of human single nucleotide polymorphism mentions with unique database identifiersIllustration of the “intervening sequence” concept in human mutation nomenclature. The example annotations for parts of the gene MECP2 (NG_007107.1) are following the IVS concept. In this nomenclature variant the adenine of the start codon is used as start position. Variations located in intronic regions start with the abbreviation “IVS” followed by the number of the intron where the variation is located. The consecutive number determines the distance to the next intron/exon boundary. Using these recommendations the two SNPs are described as –225C→A and IVS2+2T→CBack to article page