Prenatal diagnosis of pyruvate carboxylase deficiency by direct measurement of catalytic activity on chorionic villi samples.

Abstract

Pyruvate carboxylase (PC) deficiency is a rare metabolic disorder in infants and children, most frequently with fatal outcome. Its prenatal diagnosis by radiometric assay in cultured amniocytes has previously been reported. We present and discuss the prenatal diagnosis of PC deficiency by direct measurement of PC activity in chorionic villi, in two subsequent pregnancies in a family who previously lost a child affected by PC deficiency. In the next pregnancy PC was unmeasurably low in chorionic villi whereas in control samples its activity was between 0.8 and 3.3 nmol min-1 mg protein-1. Following elective termination of the pregnancy PC was shown to be totally inactive in post-mortem fetal liver. In the most recent pregnancy of the proband's mother PC was normally active in the chorionic villi. The product of this pregnancy was a normal boy.