Three different p53 polymorphisms (a codon 72 BstUI RFLP, a 16-bp dupl
ication in intron 3 and an MspI RFLP in intron 6) and haplotype combin
ations were studied in three northern European populations, viz. Finns
, Swedes and Swedish Saamis. Significant ethnic differences were found
in the codon 72 and 16-bp polymorphisms. The three polymorphisms were
in strong linkage disequilibria, all of which were highly significant
(p < 1 x 10(-18)), and ethnic differences with respect to linkage dis
equilibria were observed. Estimates of the frequencies of extended hap
lotypes showed that the most common ('wild-type') haplotype in the thr
ee populations was 2-1-2, viz, the codon 72 Arg allele linked to absen
ce of the 16-bp duplication and presence of the MspI site. There were
two additional common haplotypes, 1-1-2 and 1-2-1, and five rare haplo
types with a combined frequency of about 0.03. The present results ind
icate that extended haplotypes would be more informative in studies of
population differences and associations between p53 germline mutation
s and cancer.