Alpha-fetoprotein (AFP) is a physiologically occurring fetal glycoprotein (MW = 70,000) that is initially produced by the yolk sac and later by the fetal liver. Alpha-fetoprotein occurs physiologically during normal fetal development and decreases rapidly during the first weeks of life after birth, reaching normal adult serum levels at approximately 1 year of age1.
Neurosurgical Relevance
Germ Cell Tumors
Elevated alpha-fetoprotein in the cerebrospinal fluid is found in some germ cell tumors, such as a yolk sac tumor, which can occur in the region of the glandula pinealis2.
Testicular Metastases
16-25 % of patients with testicular tumors develop cerebral metastases, which can lead to elevated alpha-fetoprotein levels in the cerebrospinal fluid3.
Neural Tube Defects
A high maternal serum alpha-fetoprotein level (≥ 2x the median normal value for the corresponding gestational age) at 15–20 weeks' gestation results in a relative risk of 224 for a neural tube defect in the newborn4.
References
Handbook of Neurosurgery. Greenberg M, ed. 9th Edition. New York: Thieme; 2019 ↩ ↩ ↩ ↩ ↩ ↩
Milunsky A, Jick SS, Bruell CL, et al. Predictive Values, Relative Risks, and Overall Benefits of High and Low Maternal Serum Alpha-Fetoprotein Screening in Singleton Pregnancies: New epidemiologic data. Am J Obstet Gynecol. 1989;161:291-297 ↩ ↩