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Reviewed June 2008

What is the official name of the PNPO gene?

The official name of this gene is “pyridoxamine 5'-phosphate oxidase.”

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

Read more about gene names and symbols on the About page.

What is the normal function of the PNPO gene?

The PNPO gene provides instructions for producing an enzyme called pyridoxine 5'-phosphate oxidase. This enzyme is involved in the breakdown (metabolism) of vitamin B6. Specifically, it chemically modifies two forms of vitamin B6 derived from food (pyridoxine and pyridoxamine) to form pyridoxal 5'-phosphate (PLP). PLP is the active form of vitamin B6 and is necessary for many processes in the body, including protein metabolism and the production of chemicals that transmit signals in the brain (neurotransmitters). Pyridoxine 5'-phosphate oxidase is active (expressed) in cells throughout the body, with the highest amounts found in the liver.

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

pyridoxal 5'-phosphate-dependent epilepsy - caused by mutations in the PNPO gene

At least 7 mutations in the PNPO gene have been found to cause pyridoxal 5'-phosphate-dependent epilepsy. Most of these mutations change one protein building block (amino acid) in the pyridoxine 5'-phosphate oxidase enzyme, impairing its normal function. The resulting enzyme cannot effectively metabolize pyridoxine and pyridoxamine to produce PLP. A shortage of PLP can disrupt the function of many other proteins and enzymes that need PLP in order to be effective. It is not clear how the lack of PLP affects the brain and leads to the seizures that are characteristic of this condition.

Where is the PNPO gene located?

Cytogenetic Location: 17q21.32

Molecular Location on chromosome 17: base pairs 47,941,523 to 47,949,308

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The PNPO gene is located on the long (q) arm of chromosome 17 at position 21.32.

The PNPO gene is located on the long (q) arm of chromosome 17 at position 21.32.

More precisely, the PNPO gene is located from base pair 47,941,523 to base pair 47,949,308 on chromosome 17.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about PNPO?

You and your healthcare professional may find the following resources about PNPO helpful.

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

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

  • FLJ10535
  • pyridoxine 5'-phosphate oxidase

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding PNPO?

amino acid ; breakdown ; enzyme ; epilepsy ; expressed ; gene ; metabolism ; neurotransmitters ; oxidase ; phosphate ; protein

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (5 links)


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Reviewed: June 2008
Published: February 8, 2016