Hereditary persistence of alpha-fetoprotein. Case report and review of the literature.

Persistently elevated alpha-fetoprotein (AFP) levels of 24 to 30 micrograms/ml (normal < 10 micrograms/ml) were found in a 38-year-old healthy man. Subsequently, AFP was found to be elevated in another five out of 13 family members within three generations. The pedigree is consistent with an autosomal dominant inheritance pattern. No discernible disease and no functional abnormality appears to be associated with this clinically benign disorder which has been recorded in the literature on four occasions to date. The reported AFP levels in these other cases ranged from 18 to 198 micrograms/ml. Physiologically, AFP is mainly produced in the liver and the yolk sac of human fetuses more than four weeks old, with peak values of up to 4 mg/ml at 12 to 16 weeks of gestation. After birth, AFP levels usually fall, within eight to 12 months, to a very low concentration of < 10 micrograms/ml and persist at low levels throughout life. However, AFP levels can rise above normal in both children and adults in distinct conditions and diseases which will be discussed. Hereditary persistence of alpha-fetoprotein (HPAFP) should be considered in both children and adults with unexplained and persistent elevation of AFP e.g., those screened for hepatocellular carcinoma or diagnosed for germ cell tumor. It should also be recognized in AFP screening for neural tube defects or Down's syndrome during pregnancy. Hereditary persistence of AFP can be easily confirmed by analyzing AFP levels in family members.