Which condition is characterized by high levels of inhibin A?

High levels of inhibin A are associated with Down syndrome, also known as Trisomy 21. Inhibin A is a protein produced by the placenta and the ovaries, and its levels can be measured during prenatal screening tests. Elevated levels of inhibin A, particularly when considered alongside other markers such as maternal serum alpha-fetoprotein (MSAFP) and estriol, can indicate an increased risk for chromosomal abnormalities, specifically Down syndrome.

In the context of prenatal screening, the presence of high levels of inhibin A is part of the combined first-trimester screening that can help assess the likelihood of Down syndrome in a fetus. This marker is specifically valuable as it reflects placental function and abnormalities present in conditions like Down syndrome, making it a crucial factor in prenatal risk assessment.

Other conditions listed, like neural tube defects, Turner syndrome, and Edwards syndrome, do not typically present with high levels of inhibin A. Instead, they are diagnosed based on different markers and ultrasound findings. Neural tube defects often show elevated MSAFP rather than inhibin A. Turner syndrome generally involves low levels of various markers, and Edwards syndrome has distinct findings that differ from those associated with Down syndrome.