Kauppinen Raili, von und zu Fraunberg Mikael
Department of Medicine, Division of Endocrinology, University Hospital of Helsinki, 00029 HUS Helsinki, Finland.
Clin Chem. 2002 Nov;48(11):1891-900.
Acute intermittent porphyria (AIP) is a metabolic disease with clinical manifestations that mimic other abdominal, neurologic, or mental crises. We studied the diagnostic accuracy of current laboratory tests during an acute attack and in remission.
Since 1966, we have studied all known Finnish AIP patients (n = 196) and their families (n = 45) and identified the porphobilinogen deaminase (PBGD) mutation in each family. Diagnoses or exclusions of AIP were based on clinical data (including family history), biochemical tests, and in 239 cases, mutation testing. We retrospectively evaluated the diagnostic accuracy of erythrocyte PBGD activity, urinary excretion of porphobilinogen (PBG) and delta-aminolevulinic acid, and urinary and fecal excretion of porphyrins in these patients.
Measurement of urinary PBG identified all 35 AIP patients studied during an acute attack. The mean excretion of PBG was 50-fold above the reference interval, although the intraindividual increases were modest (1.6- to 4.0-fold). In the mutation-screened population, urinary PBG analysis identified only 85% of 81 AIP patients studied during remission, but by ROC curve analysis it was nonetheless the best of the biochemical tests. It was increased <or=2-fold in 29% of healthy relatives. Erythrocyte PBGD activity was decreased in only 84% of AIP patients, with results within the reference interval mainly in the variant form of AIP; it was decreased in 23% of healthy relatives.
Measurement of urinary PBG is the best biochemical test for AIP, although it is unspecific and does not distinguish AIP from other acute porphyrias. Because the acute increase in PBG is often modest, the medical history, signs, and symptoms must be evaluated carefully during an acute attack. In addition, because biochemical analyses often remain indeterminate in remission, mutation analysis is needed to exclude or confirm the diagnosis of AIP.
急性间歇性卟啉病（AIP）是一种代谢性疾病，其临床表现可模拟其他腹部、神经或精神性危象。我们研究了当前实验室检查在急性发作期和缓解期的诊断准确性。
自1966年以来，我们对所有已知的芬兰AIP患者（n = 196）及其家族（n = 45）进行了研究，并确定了每个家族中的卟胆原脱氨酶（PBGD）突变。AIP的诊断或排除基于临床数据（包括家族史）、生化检查，以及在239例患者中的突变检测。我们回顾性评估了这些患者红细胞PBGD活性、尿卟胆原（PBG）和δ-氨基-γ-酮戊酸的排泄，以及尿和粪便中卟啉的排泄的诊断准确性。
测定尿PBG可识别出在急性发作期研究的所有35例AIP患者。尽管个体内增加幅度不大（1.6至4.0倍），但PBG的平均排泄量比参考区间高50倍。在进行突变筛查的人群中，尿PBG分析仅识别出在缓解期研究的81例AIP患者中的85%，但通过ROC曲线分析，它仍是最好的生化检查。29%的健康亲属中其升高幅度≤2倍。仅84%的AIP患者红细胞PBGD活性降低，参考区间内的结果主要见于AIP的变异型；23%的健康亲属中其活性降低。
尿PBG测定是AIP最好的生化检查，尽管它缺乏特异性，且不能将AIP与其他急性卟啉病区分开来。由于PBG的急性升高通常幅度不大，在急性发作期必须仔细评估病史、体征和症状。此外，由于生化分析在缓解期常常仍不明确，需要进行突变分析以排除或确诊AIP。
