Sequence of FANCA promoter allele in the polymorphic region. Allele 1 has a single copy of a 13 base pair sequence. This has been defined as GGCCACGACGCAA in accordance with current nomenclature for mutations  although it could theoretically be GCCACGACGCAAG or CCACGACGCAAGG. Allele 2 has two tandemly arranged copies of this sequence. The 13 base pair sequence is located at -98 to -110 bases upstream of the beginning of transcription as defined by the NCBI reference sequence NM_000135.1. Exon 1 is in bold and the coding sequence in capitals.