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Genetics Home Reference: your guide to understanding genetic conditions
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FTL

Reviewed August 2012

What is the official name of the FTL gene?

The official name of this gene is “ferritin, light polypeptide.”

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

What is the normal function of the FTL gene?

The FTL gene provides instructions for making the ferritin light chain, which is one part (subunit) of a protein called ferritin. Ferritin is made up of 24 subunits formed into a hollow spherical molecule. The 24 subunits consist of varying numbers of the ferritin light chain and another subunit called the ferritin heavy chain, which is produced from another gene. The proportion of the two subunits varies in different tissues.

Ferritin stores and releases iron in cells. Each ferritin molecule can hold as many as 4,500 iron atoms inside its spherical structure. This storage capacity allows ferritin to regulate the amount of iron in cells and tissues. Iron is needed for the body to produce red blood cells.

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

hyperferritinemia-cataract syndrome - caused by mutations in the FTL gene

At least 31 mutations in the FTL gene have been identified in people with hyperferritinemia-cataract syndrome. Individuals affected by this disorder have an excess of ferritin in the blood (hyperferritinemia) and tissues of the body. A buildup of this protein begins early in life, leading to clouding of the lenses of the eyes (cataracts) in infancy.

The mutations that cause hyperferritinemia-cataract syndrome are found in a segment of the gene called the iron responsive element (IRE). The IRE normally can attach (bind) to a protein called the iron regulatory protein (IRP). When this binding occurs, the activity (expression) of the FTL gene is stopped to prevent too much ferritin light chain from being produced. This normally occurs when iron levels are low, because under those circumstances less ferritin is needed to store the iron. Mutations in the IRE segment of the FTL gene prevent it from binding with IRP, interfering with the mechanism by which ferritin production is matched to iron levels and resulting in excess ferritin being formed.

neuroferritinopathy - caused by mutations in the FTL gene

At least four mutations in the FTL gene have been identified in people with neuroferritinopathy, a disorder in which iron gradually accumulates in the brain. These mutations all affect an area of the gene known as exon 4. The most common mutation detected in people with this disorder inserts the DNA building block (nucleotide) adenine between positions 460 and 461 in the gene sequence. Researchers believe that most families with this mutation descend from a common ancestor who lived in northwest England before 1800. Three other known mutations are each found in a single individual or family affected by neuroferritinopathy.

Mutations in the FTL gene that cause neuroferritinopathy are believed to reduce ferritin's ability to store iron, resulting in the release of excess iron in nerve cells (neurons) of the brain. The cells may respond by producing more ferritin in an attempt to handle the free iron. Excess iron and ferritin accumulate in the brain, particularly in certain regions that help to control movement (basal ganglia), resulting in the movement problems and other neurological changes seen in neuroferritinopathy.

Where is the FTL gene located?

Cytogenetic Location: 19q13.33

Molecular Location on chromosome 19: base pairs 48,965,308 to 48,966,878

The FTL gene is located on the long (q) arm of chromosome 19 at position 13.33.

The FTL gene is located on the long (q) arm of chromosome 19 at position 13.33.

More precisely, the FTL gene is located from base pair 48,965,308 to base pair 48,966,878 on chromosome 19.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about FTL?

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

  • ferritin L-chain
  • ferritin light chain
  • ferritin light polypeptide-like 3
  • ferritin L subunit
  • FRIL_HUMAN
  • L apoferritin
  • MGC71996
  • NBIA3

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding FTL?

adenine ; cataract ; DNA ; exon ; gene ; iron ; molecule ; mutation ; neurological ; nucleotide ; protein ; subunit ; syndrome

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Burn J, Chinnery PF. Neuroferritinopathy. Semin Pediatr Neurol. 2006 Sep;13(3):176-81. (http://www.ncbi.nlm.nih.gov/pubmed/17101456?dopt=Abstract)
  • Cazzola M. Role of ferritin and ferroportin genes in unexplained hyperferritinaemia. Best Pract Res Clin Haematol. 2005 Jun;18(2):251-63. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15737888?dopt=Abstract)
  • Craig JE, Clark JB, McLeod JL, Kirkland MA, Grant G, Elder JE, Toohey MG, Kowal L, Savoia HF, Chen C, Roberts S, Wirth MG, Mackey DA. Hereditary hyperferritinemia-cataract syndrome: prevalence, lens morphology, spectrum of mutations, and clinical presentations. Arch Ophthalmol. 2003 Dec;121(12):1753-61. (http://www.ncbi.nlm.nih.gov/pubmed/14662596?dopt=Abstract)
  • Crompton DE, Chinnery PF, Fey C, Curtis AR, Morris CM, Kierstan J, Burt A, Young F, Coulthard A, Curtis A, Ince PG, Bates D, Jackson MJ, Burn J. Neuroferritinopathy: a window on the role of iron in neurodegeneration. Blood Cells Mol Dis. 2002 Nov-Dec;29(3):522-31. (http://www.ncbi.nlm.nih.gov/pubmed/12547246?dopt=Abstract)
  • Curtis AR, Fey C, Morris CM, Bindoff LA, Ince PG, Chinnery PF, Coulthard A, Jackson MJ, Jackson AP, McHale DP, Hay D, Barker WA, Markham AF, Bates D, Curtis A, Burn J. Mutation in the gene encoding ferritin light polypeptide causes dominant adult-onset basal ganglia disease. Nat Genet. 2001 Aug;28(4):350-4. (http://www.ncbi.nlm.nih.gov/pubmed/11438811?dopt=Abstract)
  • Koorts AM, Viljoen M. Ferritin and ferritin isoforms I: Structure-function relationships, synthesis, degradation and secretion. Arch Physiol Biochem. 2007 Feb;113(1):30-54. Review. (http://www.ncbi.nlm.nih.gov/pubmed/17522983?dopt=Abstract)
  • Levi S, Cozzi A, Arosio P. Neuroferritinopathy: a neurodegenerative disorder associated with L-ferritin mutation. Best Pract Res Clin Haematol. 2005 Jun;18(2):265-76. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15737889?dopt=Abstract)
  • Madsen E, Gitlin JD. Copper and iron disorders of the brain. Annu Rev Neurosci. 2007;30:317-37. Review. (http://www.ncbi.nlm.nih.gov/pubmed/17367269?dopt=Abstract)
  • Millonig G, Muckenthaler MU, Mueller S. Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder. Hum Genomics. 2010 Apr;4(4):250-62. Review. (http://www.ncbi.nlm.nih.gov/pubmed/20511138?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/2512)
  • OMIM: FERRITIN LIGHT CHAIN (http://omim.org/entry/134790)
  • Vidal R, Ghetti B, Takao M, Brefel-Courbon C, Uro-Coste E, Glazier BS, Siani V, Benson MD, Calvas P, Miravalle L, Rascol O, Delisle MB. Intracellular ferritin accumulation in neural and extraneural tissue characterizes a neurodegenerative disease associated with a mutation in the ferritin light polypeptide gene. J Neuropathol Exp Neurol. 2004 Apr;63(4):363-80. (http://www.ncbi.nlm.nih.gov/pubmed/15099026?dopt=Abstract)

 

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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: August 2012
Published: April 7, 2014