Alpha-Feto protein, serum

  • any type of movement disorder in early childhood, cerebellar ataxias, oculomotor apraxia(saccadic impairment)

Alpha-fetoprotein (AFP) is present in fetal serum in concentrations up to 5,000,000 μg/l. Postnatally AFP gene expression is turned down with a subsequent fall of the serum concentrations to 'adult values' of about 0.5-15 μg/l from the age of 2 years onwards. Individuals with AFP deficiency and those with hereditary persistence of AFP can however be normal. During pregnancy, AFP (in maternal serum) has long been recognized as a marker for congenital anomalies of the fetus. AFP is also a biomarker for hepatocellular carcinoma and some other malignancies.

Increased serum AFP is a biomarker for Ataxia Telangiectasia, ataxia-oculomotor apraxia 2 (AOA2), Deoxyguanosine Kinase Deficiency(DGUOK) deficiency (hepatocerebral form of mtDNA depletion). Measurement of serum AFP is very useful in the diagnostic workup of autosomal recessive cerebellar ataxias (ARCAs).

  • Classic Ataxia Telangiectasia
    • Infancy/childhood
    • ↑ AFP levels 100–900 μg/l. Rarely in <1% normal values are seen[1]
    • in Variant A-T (ATM) AFP levels are 50–500 μg/l
    • other laboratory markers include immunoglobulins, liver transaminases, chromosomal rearrangements, increased radiosensitivity
  • Ataxia with Oculomotor Apraxia Type 1 (AOA1)
    • AOA1 (APTX)
      • AFP 10-20 μg/l. ↑ AFP seen only in exceptional cases[2].
    • AOA2 (SETX)
      • Adolescence/adulthood
      • AFP 10–100 μg/l
      • ↑ Serum Creatine kinase
    • AOA2 (PIK3R5)
      • Adolescence/adulthood
      • AFP 30–100 μg/l
      • ↑ Serum Creatine kinase
    • AOA2 (none-SETX/none-PIK3R5)
      • Adolescence/adulthood
      • ↑ Serum Creatine kinase
  • Mitochondrial disorders (POLG and C10orf2)
    • infancy/childhood/adolescence/adulthood
    • raised serum/csf lactate

CSF AFP levels in normal infants also decline with gestational age in proportion to levels of AFP in serum[3][4].

  • median 61 kIU/L (5th-95th centile: 2-889 kIU/L) in infants -69 to 31 days old
  • median 1.2 kIU/L (5th-95th centile: 0.1-12.5 kIU/L) in infants 32 to 110 days old

1. a Verhagen M M M et al. Neurology. 2009 Aug 11;73(6):430-7. PMID : 19535770
2. a Schieving J H et al. Eur J Paediatr Neurol. 2014 May;18(3):243-8. PMID : 24120489
3. a Christiansen M et al. Clin Chim Acta. 2000 Jan 20;291(1):35-41. PMID : 10612715
4. a Coakley J et al. Ann Clin Biochem. 2005 Jan;42(Pt 1):24-9. PMID : 15802029
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  • Last modified: 20 months ago
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