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Alpha-Feto protein, serum
Indications
- ataxic 'cerebral palsy', any type of movement disorder in early childhood, oculomotor apraxia(saccadic impairment)
Notes
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)
- Ataxia Telangiectasia
- Infancy/childhood
- AFP levels 100–900 (normal alues are rarely seen[1])
- other laboratory markers include immunoglobulins, liver transaminases, chromosomal rearrangements, increased radiosensitivity
| Age group | Disorder (gene) | Increased serum AFP | Levels1) | Other laboratory markers2) |
|---|---|---|---|---|
| Infancy/childhood | Classic A-T (ATM) | All patientsc | 100–900 | Immunoglobulins, liver transaminases, chromosomal rearrangements, increased radiosensitivity |
| AOA1 (APTX) | Only in exceptional cases | 10–20 | Hypoalbuminaemia, hypercholesterolemia, and elevated serum CK | |
| Mitochondrial disorders (POLG and C10orf2) | Not systematically studied | Abnormalities in serum and CSF lactate and amino acids, urinary organic acids etc | ||
| Adolescence/adulthood | Variant A-T (ATM) | All patients3) | 50–500 | Chromosomal rearrangements, increased radiosensitivity |
| AOA2 (SETX) | All patients4) | 10–100 | Serum CK increased | |
| AOA2 (PIK3R5) | All patients | 30–100 | Serum CK increased | |
| AOA2 (none-SETX/none-PIK3R5) | ‘By definition’ | Serum CK increased | ||
| Mitochondrial disorders (POLG and C10orf2) | Not systematically studied | Abnormalities in serum and CSF lactate and amino acids, urinary organic acids etc |
Discussion