Free Amino Acid Levels in Amniotic Fluid of Fetuses Affected with Lowe's Syndrome or Phenylketonuria

Amniotic fluid obtained at 34th week of gestation of the fetus, which was proved to be affected with Lowe's syndrome after delivery, revealed elevated levels of most of free amino acids. This suggests a possibility of antenatal diagnosis of Lowe's syndrome by amino acid analysis of amniotic fluid, although accumulation of data is necessary especial-ly in the early stage of gestation. Amniotic fluid at 19th week of gestation of a fetus at risk which was subsequently confirmed to be a homozygote of phenylke-tonuria showed normal levels of phenylalanine and tyrosine. This indicates the difficulty of prenatal diagnosis of phenylketonuria. Amniotic fluid was obtained at 20th week of gestation from a pregnant woman who had previously borne a child with hyperalaninemia with pyruvicemia due to a deficiency of pyruvate carboxylase in the liver. The concentrations of alanine, pyruvate and lactate in amniotic fluid were found to be within normal range; consequently she was delivered of a healthy girl.