Acute intermittent porphyria caused by a C----T mutation that produces a stop codon in the porphobilinogen deaminase gene

A mutation of the porphobilinogen (PBG) deaminase gene that produces the cross-reacting immunological material (CRIM)-negative type of acute intermittent porphyria (AIP) has been identified in one of 43 unrelated patients with this form of the disorder. The mutation is a C---T transition that abolishes a PstI recognition site in exon 9 of the gene and converts a codon for glutamine to a stop codon.