Alkaline phosphatase, liver/bone/kidney (ALPL)

The ALPL gene provides instructions for making an enzyme called alkaline phosphatase. This enzyme plays an important role in the growth and development of bones and teeth. It is also active in many other tissues, particularly in the liver and kidneys. This enzyme acts as a phosphatase, which means that it removes clusters of oxygen and phosphorus atoms (phosphate groups) from other molecules.

Alkaline phosphatase is essential for the process of mineralization, in which minerals such as calcium and phosphorus are deposited in developing bones and teeth. Mineralization is critical for the formation of bones that are strong and rigid and teeth that can withstand chewing and grinding.

What is the official name of the ALPL gene?

The official name of this gene is “alkaline phosphatase, liver/bone/kidney.”

ALPL is the gene's official symbol. The ALPL gene is also known by other names, listed below.

How are changes in the ALPL gene related to health conditions?

hypophosphatasia - caused by mutations in the ALPL gene

More than 190 mutations in the ALPL gene have been identified in people with hypophosphatasia. About 80 percent of these mutations change a single protein building block (amino acid) in the alkaline phosphatase enzyme. Other mutations insert or delete genetic material in the ALPL gene or change the way the gene's instructions are used to build the enzyme.

Mutations in the ALPL gene lead to the production of an abnormal version of alkaline phosphatase that cannot participate effectively in the mineralization of developing bones and teeth. A shortage of alkaline phosphatase allows substances that are normally processed by the enzyme to build up abnormally in the body. Researchers believe that a buildup of one of these compounds, inorganic pyrophosphate, underlies the defective mineralization of bones and teeth in people with hypophosphatasia.

ALPL mutations that almost completely eliminate the activity of alkaline phosphatase usually result in the more severe forms of hypophosphatasia. Other mutations, which reduce but do not eliminate the activity of the enzyme, are often responsible for milder forms of the condition.

Where is the ALPL gene located?

Cytogenetic Location: 1p36.1-p34

Molecular Location on chromosome 1: base pairs 21,708,455 to 21,777,488

The ALPL gene is located on the short (p) arm of chromosome 1 between positions 36.1 and 34.

More precisely, the ALPL gene is located from base pair 21,708,455 to base pair 21,777,488 on chromosome 1.

What other names do people use for the ALPL gene or gene products?

• alkaline phosphomonoesterase
• AP-TNAP
• glycerophosphatase
• HOPS
• MGC161443
• PPBT_HUMAN
• tissue non-specific alkaline phosphatase
• tissue-nonspecific ALP
• TNAP
• TNSALP

External Links

Where can I find additional information about ALPL? You and your healthcare professional may find the following resources about ALPL helpful.

• Gene Tests - DNA tests ordered by healthcare professionals

You may also be interested in these resources, which are designed for genetics professionals and researchers.

• PubMed - Recent literature
• OMIM - Genetic disorder catalog
• Research Resources - Tools for researchers (5 links)

See How are genetic conditions and genes named? in the Handbook.

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

• What is DNA?
• What is a gene?
• How do genes direct the production of proteins?
• How can gene mutations affect health and development?

These links provide additional genetics resources that may be useful.

• Genetics education
• Human Genome Project
• Resources for Genetic Researchers

What glossary definitions help with understanding ALPL?

acids ; amino acid ; atom ; calcium ; compound ; enzyme ; gene ; kidney ; mineral ; molecule ; mutation ; oxygen ; phosphatase ; phosphate ; phosphomonoesterase ; phosphorus ; protein ; tissue

References

• Brun-Heath I, Taillandier A, Serre JL, Mornet E. Characterization of 11 novel mutations in the tissue non-specific alkaline phosphatase gene responsible for hypophosphatasia and genotype-phenotype correlations. Mol Genet Metab. 2005 Mar;84(3):273-7. Epub 2004 Dec 19. PubMed citation
• Mornet E, Stura E, Lia-Baldini AS, Stigbrand T, Menez A, Le Du MH. Structural evidence for a functional role of human tissue nonspecific alkaline phosphatase in bone mineralization. J Biol Chem. 2001 Aug 17;276(33):31171-8. Epub 2001 Jun 6. PubMed citation
• Mornet E. Hypophosphatasia: the mutations in the tissue-nonspecific alkaline phosphatase gene. Hum Mutat. 2000;15(4):309-15. Review. PubMed citation
• Spentchian M, Brun-Heath I, Taillandier A, Fauvert D, Serre JL, Simon-Bouy B, Carvalho F, Grochova I, Mehta SG, Muller G, Oberstein SL, Ogur G, Sharif S, Mornet E. Characterization of missense mutations and large deletions in the ALPL gene by sequencing and quantitative multiplex PCR of short fragments. Genet Test. 2006 Winter;10(4):252-7. PubMed citation
• Spentchian M, Merrien Y, Herasse M, Dobbie Z, Glaser D, Holder SE, Ivarsson SA, Kostiner D, Mansour S, Norman A, Roth J, Stipoljev F, Taillemite JL, van der Smagt JJ, Serre JL, Simon-Bouy B, Taillandier A, Mornet E. Severe hypophosphatasia: characterization of fifteen novel mutations in the ALPL gene. Hum Mutat. 2003 Jul;22(1):105-6. PubMed citation
• Whyte MP. Hypophosphatasia and the role of alkaline phosphatase in skeletal mineralization. Endocr Rev. 1994 Aug;15(4):439-61. Review. No abstract available. PubMed citation