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Reviewed April 2014

What is the official name of the PFKM gene?

The official name of this gene is “phosphofructokinase, muscle.”

PFKM is the gene's official symbol. The PFKM 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 PFKM gene?

The PFKM gene provides instructions for making one piece (the PFKM subunit) of an enzyme called phosphofructokinase. This enzyme plays a role in the breakdown of a complex sugar called glycogen, which is a major source of stored energy in the body. The phosphofructokinase enzyme is made up of four subunits and is found in a variety of tissues. Different combinations of subunits are found in different tissues. In muscles used for movement (skeletal muscles), the phosphofructokinase enzyme is composed solely of subunits produced from the PFKM gene.

The cells' main source of energy is stored as glycogen. Glycogen can be broken down rapidly into the simple sugar glucose when energy is needed, for instance to maintain normal blood sugar levels between meals or for energy during exercise. Phosphofructokinase composed of PFKM subunits is involved in the sequence of events that breaks down glycogen to provide energy to muscle cells. Specifically, the enzyme converts a molecule called fructose-6-phosphate to a molecule called fructose 1,6-bisphosphate.

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

glycogen storage disease type VII - caused by mutations in the PFKM gene

At least 20 mutations in the PFKM gene have been found to cause glycogen storage disease type VII (GSDVII). This condition is characterized by an inability to break down glycogen in muscle cells, resulting in muscle cramps and weakness that can vary in severity among affected individuals. PFKM gene mutations that cause GSDVII result in the production of PFKM subunits that have little or no function. One PFKM gene mutation accounts for most cases of GSDVII in people with Ashkenazi Jewish ancestry. This mutation (written as IVS5+1G>A) results in a small deletion of genetic material within the gene, which alters the way the gene's instructions are pieced together and causes a nonfunctional subunit to be produced.

Without functional PFKM subunits, no functional phosphofructokinase is formed in skeletal muscles and glycogen cannot be completely broken down. Partially broken down glycogen builds up in muscle cells. Muscles that do not have access to glycogen as an energy source become weakened and cramped following moderate strain, such as exercise, and in some cases, begin to break down. In other tissues, other subunits that make up the phosphofructokinase enzyme likely compensate for the lack of PFKM subunits, and the enzyme is able to retain some function. This compensation may help explain why other tissues are not affected by PFKM gene mutations. It is unclear why some individuals with GSDVII are more severely affected than others.

Where is the PFKM gene located?

Cytogenetic Location: 12q13.3

Molecular Location on chromosome 12: base pairs 48,105,402 to 48,146,404

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

The PFKM gene is located on the long (q) arm of chromosome 12 at position 13.3.

The PFKM gene is located on the long (q) arm of chromosome 12 at position 13.3.

More precisely, the PFKM gene is located from base pair 48,105,402 to base pair 48,146,404 on chromosome 12.

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

Where can I find additional information about PFKM?

You and your healthcare professional may find the following resources about PFKM 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 PFKM gene or gene products?

  • 6-phosphofructo-1-kinase
  • 6-phosphofructokinase, muscle type
  • PFK1
  • PFK-1
  • PFKA
  • PFK-A
  • PFKX
  • phosphofructo-1-kinase isozyme A
  • phosphofructokinase 1
  • phosphofructokinase-M
  • phosphofructokinase, polypeptide X
  • phosphohexokinase

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 PFKM?

Ashkenazi Jewish ; breakdown ; deletion ; enzyme ; fructose ; gene ; glucose ; glycogen ; isozyme ; kinase ; molecule ; muscle cells ; mutation ; phosphate ; simple sugar ; subunit

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: April 2014
Published: February 8, 2016