Development of an internal restriction control in the PCR detection of the prothrombin 20210A mutation

Detection of the presence of the 20210A/G allele in the human prothrombin gene is easily achieved by amplification using primers designed to span this region. The downstream primer creates a HindIII restriction site if the 20210A variant is present. A new forward upstream primer was designed to incorporate a naturally occurring HindIII site that, as it is present in both alleles, serves as an internal restriction control. Using this technique, the DNA of 292 unselected patients with venous thromboembolic disease was analysed. Of the 149 white patients, 4.7% were heterozygous for this mutation but none of the African Black patients were positive.