Brock D J, Clarke H A, Barron L
Human Genetics Unit, University of Edinburgh, Western General Hospital, UK.
Hum Genet. 1988 Mar;78(3):271-5. doi: 10.1007/BF00291675.
Prenatal diagnosis of cystic fibrosis by microvillar enzyme assay on amniotic fluid supernatant has been carried out on 258 sequential pregnancies with a 1 in 4 recurrence risk, all with known outcome. In general the three enzymes evaluated, gamma-glutamyltranspeptidase, aminopeptidase M and the intestinal isoenzyme of alkaline phosphatase, showed a high degree of concordance. However, there were two unusual patterns of microvillar enzyme activity; in seven cases a low gamma-glutamyltranspeptidase activity was associated with elevated values of intestinal alkaline phosphatase, and in ten cases there were isolated low values of intestinal alkaline phosphatase. The former pattern was found to be associated with cystic fibrosis in five cases, while the latter was associated with a normal outcome in all ten cases. A retrospective analysis of enzyme values suggested that the optimal system for minimizing false positives and false negatives was to define foetal cystic fibrosis as a sample where two of the three microvillar enzymes were below a cut-off of half the median value for the gestational week. If such scoring were applied to the cases where conventional microvillar enzyme patterns were observed, the false positive rate was 2.3% and the false negative rate 4.4% between 17 and 20 weeks of gestation.
通过对羊水上清液进行微绒毛酶分析对258例连续妊娠进行了囊性纤维化的产前诊断，这些妊娠的复发风险为1/4，且所有妊娠结局均已知。总体而言，所评估的三种酶，即γ-谷氨酰转肽酶、氨肽酶M和碱性磷酸酶的肠同工酶，显示出高度的一致性。然而，存在两种异常的微绒毛酶活性模式；在7例中，γ-谷氨酰转肽酶活性低与肠碱性磷酸酶值升高相关，在10例中，存在孤立的肠碱性磷酸酶低值。发现前一种模式在5例中与囊性纤维化相关，而后一种模式在所有10例中均与正常结局相关。对酶值的回顾性分析表明，将胎儿囊性纤维化定义为三种微绒毛酶中有两种低于孕周中位数一半的临界值的样本，是将假阳性和假阴性降至最低的最佳系统。如果将这种评分应用于观察到传统微绒毛酶模式的病例，在妊娠17至20周之间，假阳性率为2.3%，假阴性率为4.4%。
