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Alpha-Feto protein, serum
Indications
- any type of movement disorder in early childhood, cerebellar ataxias, 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)
- 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
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- infancy/childhood/adolescence/adulthood
- raised serum/csf lactate
Discussion