Scientific Nomenclature

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Blood generally follows the Human Genome Variation Society’s mutation nomenclature recommendations for nucleotides.

Nucleotides are represented by the letters A, C, G, and T; lowercase letters are allowed (to indicate uncertainty in the base call).

Denote nucleotide substitutions and polymorphisms by putting the nucleotide number first and then using a greater-than symbol between the replaced nucleotide and the new nucleotide; all elements should be closed up.


To indicate that a genomic DNA or complementary DNA sequence is used, include “(gDNA [or cDNA] sequence, first described by        ref#)”; do not preface nucleotide substitutions with the letter g or c.

Denote nucleotide insertions by putting the 2 surrounding nucleotide numbers in front, separated by a hyphen, followed by "ins" and the inserted nucleotide.


Denote nucleotide deletions by specifying the nucleotide number deleted, followed by "del" and the deleted nucleotide.


Denote nucleotide codon changes using the substitution scheme above:


See the Human Genome Variation Society website for how to handle other situations (eg, intron mutations and IVS-intervening sequences).

Amino acids

In mutation notation, it is acceptable to use abbreviations without expansion (see Amino acid abbreviations), but follow abbreviations rules elsewhere.

Amino acids may be abbreviated with 1-letter abbreviations or 3-letter abbreviations. Amino acid abbreviations details both abbreviation schemes. Authors should try to use the same scheme consistently throughout an article, though variation is allowed.

A codon number may be used to describe a mutation.


If the codon number is not used, then denote the mutation with a full arrow.


If a stop codon is discussed, note that it is sometimes denoted by an abbreviation for unspecified amino acid (Xaa or X); if so, ensure that this abbreviation is consistent with surrounding amino acid abbreviations. Note that other notation is sometimes used (eg, “Stop”).


Amino acid abbreviations

alanine Ala A
arginine Arg R
asparagine Asn N
aspartic acid Asp D
cysteine Cys C
glutamic acid Glu E
glutamine Gln Q
glycine Gly G
histidine His H
isoleucine Ile I
leucine Leu L
lysine Lys K
methionine Met M
phenylalanine Phe F
proline Pro P
serine Ser S
threonine Thr T
tryptophan Trp W
tyrosine Tyr Y
valine Val V
unspecified aa Xaa X