Amniotic fluid gamma-glutamyl transpeptidase activity during the second trimester

Area of Science:

• Biochemistry
• Prenatal Diagnostics
• Genetics

Background:

• Gamma glutamyl transpeptidase (GGTP) is an enzyme found in various tissues.
• Amniotic fluid composition changes during pregnancy and can reflect fetal well-being.
• Assessing fetal health often involves analyzing biochemical markers in amniotic fluid.

Purpose of the Study:

• To investigate the relationship between Gamma glutamyl transpeptidase (GGTP) activity in second-trimester amniotic fluid and fetal abnormalities.
• To determine if GGTP levels can serve as a preliminary screening tool for certain fetal chromosomal abnormalities.

Main Methods:

• Collected second-trimester amniotic fluid samples from normal and abnormal fetuses.
• Measured Gamma glutamyl transpeptidase (GGTP) activity in all samples.
• Correlated GGTP activity with gestational age, meconium/fetal blood contamination, and specific fetal diagnoses.

Main Results:

• GGTP activity decreased with advancing gestation.
• Meconium and fetal blood contamination increased GGTP activity; maternal blood did not affect it.
• Significantly lower GGTP activity was observed in fetuses with spina bifida, trisomy 18, translocation Down syndrome, and gastroschisis. Anencephaly showed no significant change. Klinefelter's and Turner's syndromes were near the 50th percentile, and trisomy 21 was below the 40th percentile.

Conclusions:

• Second-trimester amniotic fluid GGTP activity is influenced by gestational age and contamination.
• Abnormally low GGTP levels are associated with specific fetal abnormalities, including certain chromosome disorders.
• Amniotic fluid GGTP may offer a simple preliminary screening method for detecting potential fetal chromosomal abnormalities.