Wolff C, Piderit F, Armas-Merino R
Department of Medicine, Universidad de Chile, Hospital San Juan de Dios, Santiago.
Eur J Clin Chem Clin Biochem. 1991 May;29(5):313-5. doi: 10.1515/cclm.1991.29.5.313.
Erythrocyte porphobilinogen synthase deficiency was confirmed by the determination of its activity in blood and also by the high levels of both porphyrins and 5-aminolaevulinic acid in the urine of two siblings. They presented with a picture of porphyric attack characterized by abdominal colic pain, high blood pressure, tachycardia and severe constipation. The profile of both porphyrins and their precursors in urine and blood resembled lead poisoning. However, this was ruled out because both patients had normal blood levels of lead. Furthermore, porphobilinogen synthase activity did not normalize when it was determined in the presence of dithiothreitol or dithiothreitol plus zinc chloride. No other causes to account for a deficiency in porphobilinogen synthase activity were identified. The simultaneous occurrence of similar clinical and biochemical symptoms suggests that the same triggering factor was present. Because the activity of porphobilinogen synthase was less than 4% of normal values, it is possible that these patients were homozygotes with respect to this defect, which could explain the presence of clinical symptoms. We propose that this metabolic defect is not uncommon and it should be kept in mind when diagnosing of porphyrias or heavy metal intoxications.
通过测定血液中红细胞卟胆原合酶的活性，以及两名同胞尿液中卟啉和5-氨基酮戊酸的高水平，确诊为红细胞卟胆原合酶缺乏症。他们表现出卟啉病发作的症状，特征为腹部绞痛、高血压、心动过速和严重便秘。尿液和血液中卟啉及其前体的谱图类似于铅中毒。然而，由于两名患者血液中的铅水平正常，因此排除了铅中毒。此外，当在二硫苏糖醇或二硫苏糖醇加氯化锌存在的情况下测定时，卟胆原合酶活性并未恢复正常。未发现其他导致卟胆原合酶活性缺乏的原因。相似临床和生化症状的同时出现表明存在相同的触发因素。由于卟胆原合酶的活性低于正常值的4%，这些患者很可能是该缺陷的纯合子，这可以解释临床症状的出现。我们认为这种代谢缺陷并不罕见，在诊断卟啉病或重金属中毒时应予以考虑。
