AFP decreased is associated with which prenatal condition?

AFP decreased is associated with which prenatal condition?

• A. Trisomy 21 (Down)
• B. Trisomy 18 (Edwards)
• C. Trisomy 13 (Patau)
• D. Normal karyotype

Answer: (A)

Fetal screening uses maternal serum alpha-fetoprotein (AFP) to identify risks for certain conditions. AFP is produced by the fetus and rises in the mother’s blood when there are open neural tube or ventral wall defects. Conversely, a decreased AFP level is classically associated with Down syndrome (trisomy 21). In the common screening pattern for Down syndrome, AFP is lowered while other markers (like hCG) are elevated or altered, helping distinguish this condition from a normal karyotype, where AFP would typically be in the normal range. While other trisomies can show variations in AFP patterns, the most characteristic and tested association is with Down syndrome.

Fetal screening uses maternal serum alpha-fetoprotein (AFP) to identify risks for certain conditions. AFP is produced by the fetus and rises in the mother’s blood when there are open neural tube or ventral wall defects. Conversely, a decreased AFP level is classically associated with Down syndrome (trisomy 21). In the common screening pattern for Down syndrome, AFP is lowered while other markers (like hCG) are elevated or altered, helping distinguish this condition from a normal karyotype, where AFP would typically be in the normal range. While other trisomies can show variations in AFP patterns, the most characteristic and tested association is with Down syndrome.