Red blood cell porphobilinogen deaminase in the evaluation of acute intermittent porphyria
C. A. Pierach, M. K. Weimer, R. A. Cardinal, I. C. Bossenmaier, J. R. Bloomer and J. R. Blommer
We measured the activity of the enzyme porphobilinogen deaminase in red
blood cells of 222 persons. Ninety-seven of 107 patients with acute
intermittent porphyria had enzyme activity below the normal range, whereas
55 of 56 patients with other types of porphyria had normal activity. This
underscores the utility of this test in confirming the diagnosis of acute
intermittent porphyria. Measurement of enzyme activity in 41 families with
acute intermittent porphyria demonstrated that deficient activity is
inherited as an autosomal dominant trait. Many latent carriers of the
genetic defect were identified by family studies, permitting appropriate
precautions to avoid potentially lethal porphyric attacks.
