Detection of four mutations in six unrelated South African patients with acute intermittent porphyria

Abstract We have screened the hydroxymethylbilane synthase cDNA from six South African patients with acute intermittent porphyria, using a combination of chemical cleavage mismatch analysis and direct sequencing of asymmetrically amplified PCR products. Four mutations were detected, a novel T insertion (771insT) and three missense mutations (R26H, R116W and R173Q). The 771insT mutation produces a stop codon, thirty-three codons downstream and a loss of approximately 20% of the protein is predicted. The R116W mutation, which was found to have a high prevalence in the Dutch population, was detected in three unrelated South African patients.