Nucleotide change - Nucleotide numbers are given in relation to the reference sequence in the NCBI database, as indicated in the RefSeq column, and we have used the numbering convention as recommended by Antonarakis (Hum Mutat 1998;11:1-3) whereby the A of the start codon is +1. For example the T/C SNP coding for HPA-1 is at position 196 in the RefSeq sequence, but because this sequence includes 20 nucleotides upstream of the start codon, the SNP is designated at position 176 in the table above. Therefore, it is likely that the nucleotide positions given above are different to the numbers in the original publication describing the mutation.
Nucleotide and protein substitutions are shown as changes from the more common form (a) to the less common form (b). In certain cases, e.g. HPA-5, the reference sequence encodes the less common form.