Haem precursors and porphobilinogen deaminase in erythrocytes and lymphocytes of patients with acute intermittent porphyria.

Patients with AIP can be subdivided into three different groups concerning their PBGD activity in erythrocytes: The first of which has lowered, the second overlapping and the third normal PBGD activity. Out of 385 AIP patients 87% had lowered, 8% had overlapping and 5% had normal PBGD activity. Gene carriers of AIP having slight, moderate or high metabolic aberrations of excretion parameters are recognized by analysis of urinary haem precursors and faecal porphyrins. The haem precursor excretion of the groups with lowered, overlapping and normal PBGD activity in erythrocytes compared to each other is not significantly different but differs significantly (p < 0.001) from the normal values. One individual suffering from AIP was detected in a family with normal PBGD. Lymphocytes can be stored in liquid nitrogen for 3 months without loss of PBGD activity. Specific PBGD activity in lymphocytes is 5% from specific PBGD activity in erythrocytes. In AIP patients with lowered specific PBGD activity in erythrocytes specific PBGD activity is lowered to the same extent in their lymphocytes.