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| ====== Alpha-Feto protein, serum ====== | ====== Alpha-Feto protein, serum ====== |
| <alert type="warning" icon="glyphicon glyphicon-hand-down">This article is a stub. Please help us improve it</alert> | |
| {{tag>labtests}} | {{tag>labtests}} |
| ==== Indications ==== | ==== Indications ==== |
| * [[ataxic 'cerebral palsy']], any type of movement disorder in early childhood, [[oculomotor apraxia]](saccadic impairment) | * any type of movement disorder in early childhood, cerebellar ataxias, [[oculomotor apraxia]](saccadic impairment) |
| ==== Notes ==== | ==== Notes ==== |
| * ↑ in [[ataxia-telangiectasia]], [[ataxia-oculomotor apraxia 2]] (AOA2) and [[Deoxyguanosine Kinase Deficiency]](DGUOK) deficiency (hepatocerebral form of mtDNA depletion) | Alpha-fetoprotein (AFP) is present in fetal serum in concentrations up to 5,000,000 μg/l. Postnatally [[https://ghr.nlm.nih.gov/gene/AFP|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. |
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| 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). |
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| Increased serum AFP is a biomarker for Ataxia Telangiectasia, [[ataxia-oculomotor apraxia 2]] (AOA2) | * **Classic Ataxia Telangiectasia** |
| There are at least four neurodegenerative disorders, all inherited as autosomal recessive traits and characterized by the presence of cerebellar ataxia, abnormal ocular movements, and neuropathy, for which an elevated concentration of serum AFP is an important diagnostic biomarker. | * Infancy/childhood |
| <table label> | * ↑ AFP levels 100–900 μg/l. Rarely in <1% normal values are seen[(:cite:19535770>{{pmid>long:19535770}})] |
| ^ Age group ^ Disorder (gene) ^ Increased serum AFP ^ Levels[(1>The concentration range that is given is based on the available literature and own experiences; it is meant to give a global impression (note: reference values from the age of 2 years: 0.5 to circa 15 μg/l)] ^ Other laboratory markers[(2>Additional markers are generally not abnormal in all patients)] | | * in Variant A-T (ATM) AFP levels are 50–500 μg/l |
| | Infancy/childhood | Classic A-T (ATM) | All patientsc | 100–900 | Immunoglobulins, liver transaminases, chromosomal rearrangements, increased radiosensitivity | | * other laboratory markers include immunoglobulins, liver transaminases, chromosomal rearrangements, increased radiosensitivity |
| | | AOA1 (APTX) | Only in exceptional cases | 10–20 | Hypoalbuminaemia, hypercholesterolemia, and elevated serum CK | | * **Ataxia with Oculomotor Apraxia Type 1 (AOA1)** |
| | | Mitochondrial disorders (POLG and C10orf2) | Not systematically studied | | Abnormalities in serum and CSF lactate and amino acids, urinary organic acids etc | | * AOA1 (APTX) |
| | Adolescence/adulthood | Variant A-T (ATM) | All patients[(3>Exceptional cases (<1% of all cases reported sofar) with normal serum AFP have been reported (see text for references))] | 50–500 | Chromosomal rearrangements, increased radiosensitivity | | *AFP 10-20 μg/l. ↑ AFP seen only in exceptional cases[(:cite:24120489>{{pmid>long:24120489}})]. |
| | | AOA2 (SETX) | All patients[(4>AFP >7 μg/l in >99%)] | 10–100 | Serum CK increased | | * AOA2 (SETX) |
| | | AOA2 (PIK3R5) | All patients | 30–100 | Serum CK increased | | * Adolescence/adulthood |
| | | AOA2 (none-SETX/none-PIK3R5) | ‘By definition’ | | Serum CK increased | | * AFP 10–100 μg/l |
| | | Mitochondrial disorders (POLG and C10orf2) | Not systematically studied | | Abnormalities in serum and CSF lactate and amino acids, urinary organic acids etc | | * ↑ Serum Creatine kinase |
| <caption>Neurodegenerative disorders characterized by increased serum AFP concentrations[(:cite:24120489>{{pubmed>long:24120489}})]</caption> | * AOA2 (PIK3R5) |
| </table> | * Adolescence/adulthood |
| ==== References ==== | * AFP 30–100 μg/l |
| ~~REFNOTES~~ | * ↑ Serum Creatine kinase |
| | * AOA2 (none-SETX/none-PIK3R5) |
| | * Adolescence/adulthood |
| | * ↑ Serum Creatine kinase |
| | * **Mitochondrial disorders ([[https://ghr.nlm.nih.gov/gene/POLG|POLG]] and [[https://www.ncbi.nlm.nih.gov/gene/425626|C10orf2]])** |
| | * infancy/childhood/adolescence/adulthood |
| | * raised serum/csf lactate |
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| | CSF AFP levels in normal infants also decline with gestational age in proportion to levels of AFP in serum[(:cite:PMID10612715>{{pmid>long:10612715}})][(:cite:15802029>{{pmid>long:15802029}})]. |
| | * 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 |
