Figure 1

Identification of a novel NAT1 allele. (a) A 344 bp PCR product of NAT1 (amplified from genomic DNA using primers N769 and N1113, the latter introducing an additional Mbo II restriction site in NAT1*4) was digested with Mbo II and separated on a 4% (w/v) MetaPhor^® agarose (FMC BioProducts, UK)/0.5X TBE gel, against a 1 kb DNA Ladder (Gibco BRL, UK)(Lane M). Detectable NAT1*4 fragments are 176 bp and 125 bp. Fragments of other known alleles are 176 bp and 144 bp (NAT1*3, NAT1*10, NAT1*14A) or 176 bp and 135 bp (NAT1*11A). The individual marked with an open arrow had a novel restriction fragment (116 bp) which did not correspond to any known allelic combination. (b) Both NAT1 alleles of the individual marked with an open arrow were sequenced across the coding and 5' and 3' flanking regions and the sequence of the novel allele (NAT1*11B) is illustrated in comparison with the most common Caucasian NAT1 allele, NAT1*4 (EMBL Accession Number AJ307007) and the most similar NAT1 allele, NAT1*11A. NAT1*11B contains sequence variations identical to those of NAT1*11A (C-344T, A-40T, G445A, G459A, T640G and a 9 base deletion (Δ) in the nucleotide range 1065–1090, compared with the NAT1*4 sequence), but contains a cytosine at nucleotide 1095. The 870 bp coding region of NAT1 is shaded grey, with 438 nucleotides upstream and 306 nucleotides downstream also shown.