Prenatal diagnosis of cystic fibrosis by analysis of microvillar enzymes of the amniotic fluid

Prenatal diagnosis was performed in 92 pregnancies high-risk for cystic fibrosis during six years. Amniotic fluid samples obtained by amniocentesis were examined with regard to their microvillar membrane enzyme activity. However, trehalase, alkaline phosphatase isoenzymes and L-gamma-glutamyl-transferase in the amniotic fluid are not specific markers of the cystic fibrosis, their activity is significantly lower than in normal pregnancies. By measuring the three enzymes simultaneously, sensitivity, specificity and reliability of the method were found to be over 92%. It is concluded that the mid-trimester amniotic fluid diagnosis is useful for some heterozygotic couples for cystic fibrosis even in the possession of the DNA methods.