Which protein is normally produced by the fetus but is found increased in amniotic fluid in cases of spina bifida?

Which protein is normally produced by the fetus but is found increased in amniotic fluid in cases of spina bifida?

• A. a1-Antitrypsin
• B. a1-Acid glycoprotein
• C. a1-Fetoprotein
• D. a2-Macroglobulin

Answer: (C)

Fetal alpha-fetoprotein is a protein normally produced by the fetus (by the liver and yolk sac) and is present in amniotic fluid. In cases of open neural tube defects such as spina bifida, this fetal protein leaks into the amniotic fluid, causing elevated AFP levels there. That direct association with fetal origin and leakage into amniotic fluid makes AFP the best marker for spina bifida. The other listed proteins are not specific markers for this condition: they are produced for other physiological roles (such as general liver synthesis or acute-phase responses) and do not rise in amniotic fluid due to open neural tube defects.

Fetal alpha-fetoprotein is a protein normally produced by the fetus (by the liver and yolk sac) and is present in amniotic fluid. In cases of open neural tube defects such as spina bifida, this fetal protein leaks into the amniotic fluid, causing elevated AFP levels there. That direct association with fetal origin and leakage into amniotic fluid makes AFP the best marker for spina bifida. The other listed proteins are not specific markers for this condition: they are produced for other physiological roles (such as general liver synthesis or acute-phase responses) and do not rise in amniotic fluid due to open neural tube defects.