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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 ==== |
| 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. | 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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| 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) | 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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| <table label> | * **Classic Ataxia Telangiectasia** |
| ^ Age group ^ Disorder (gene) ^ Increased serum AFP ^ Levels[(1>The concentration range is based on the available literature (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)] | | * Infancy/childhood |
| | Infancy/childhood | Classic A-T (ATM) | All patientsc | 100–900 | Immunoglobulins, liver transaminases, chromosomal rearrangements, increased radiosensitivity | | * ↑ AFP levels 100–900 μg/l. Rarely in <1% normal values are seen[(:cite:19535770>{{pmid>short:19535770}})] |
| | | AOA1 (APTX) | Only in exceptional cases | 10–20 | Hypoalbuminaemia, hypercholesterolemia, and elevated serum CK | | * in Variant A-T (ATM) AFP levels are 50–500 μg/l |
| | | Mitochondrial disorders (POLG and C10orf2) | Not systematically studied | | Abnormalities in serum and CSF lactate and amino acids, urinary organic acids etc | | * other laboratory markers include immunoglobulins, liver transaminases, chromosomal rearrangements, increased radiosensitivity |
| | Adolescence/adulthood | Variant A-T (ATM) | All patients[(3>Exceptional cases (<1% of all cases reported sofar) with normal serum AFP have been reported)] | 50–500 | Chromosomal rearrangements, increased radiosensitivity | | * **Ataxia with Oculomotor Apraxia Type 1 (AOA1)** |
| | | AOA2 (SETX) | All patients[(4>AFP >7 μg/l in >99%)] | 10–100 | Serum CK increased | | * AOA1 (APTX) |
| | | AOA2 (PIK3R5) | All patients | 30–100 | Serum CK increased | | *AFP 10-20 μg/l. ↑ AFP seen only in exceptional cases[(:cite:24120489>{{pmid>short:24120489}})]. |
| | | AOA2 (none-SETX/none-PIK3R5) | ‘By definition’ | | Serum CK increased | | * AOA2 (SETX) |
| | | Mitochondrial disorders (POLG and C10orf2) | Not systematically studied | | Abnormalities in serum and CSF lactate and amino acids, urinary organic acids etc | | * Adolescence/adulthood |
| <caption>Neurodegenerative disorders characterized by increased serum AFP concentrations[(:cite:24120489>{{pubmed>long:24120489}})]</caption> | * AFP 10–100 μg/l |
| </table> | * ↑ Serum Creatine kinase |
| ==== References ==== | * AOA2 (PIK3R5) |
| ~~REFNOTES~~ | * Adolescence/adulthood |
| | * AFP 30–100 μg/l |
| | * ↑ 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 |
| | |
| | CSF AFP levels in normal infants also decline with gestational age in proportion to levels of AFP in serum[(:cite:PMID10612715>{{pmid>short:10612715}})][(:cite:15802029>{{pmid>short: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 |
