Second trimester maternal dimeric inhibin-A in the multiple-marker screening test for Down's syndrome

Area of Science:

• Biochemistry
• Genetics
• Obstetrics

Background:

• Second trimester screening is crucial for detecting fetal Down's syndrome.
• Current multiple-marker screening uses specific biochemical markers.
• Dimeric inhibin-A is a potential marker for chromosomal abnormalities.

Purpose of the Study:

• To evaluate the added value of serum dimeric inhibin-A concentration in second-trimester screening for Down's syndrome.
• To compare the performance of dimeric inhibin-A against existing markers in the triple test.
• To investigate if dimeric inhibin-A offers improved detection rates for Down's syndrome.

Main Methods:

• Screened 1156 maternal serum samples for dimeric inhibin-A.
• Compared dimeric inhibin-A with the routine triple test (alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin).
• Assessed performance by substituting unconjugated estriol with inhibin-A and using inhibin-A with alpha-fetoprotein.

Main Results:

• Maternal serum dimeric inhibin-A concentrations were significantly higher in Down's syndrome pregnancies.
• The combination of dimeric inhibin-A with the multiple-marker screening test showed limited additional value.
• This limitation is attributed to the strong correlation between dimeric inhibin-A and intact human chorionic gonadotropin.

Conclusions:

• Dimeric inhibin-A levels are elevated in Down's syndrome pregnancies during the second trimester.
• Its strong correlation with human chorionic gonadotropin limits its independent additional value in current screening protocols.
• Further research may be needed to optimize its use or explore alternative combinations for Down's syndrome screening.