KLLN

Reviewed October 2012

What is the official name of the KLLN gene?

The official name of this gene is “killin, p53-regulated DNA replication inhibitor.”

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

What is the normal function of the KLLN gene?

The KLLN gene provides instructions for making a protein called killin. The activity of the KLLN gene is controlled by a protein called p53 (which is produced from the TP53 gene). Little is known about the function of killin, although it is thought to trigger cells to self-destruct (undergo apoptosis) when they are damaged or no longer needed. In this way, killin helps to prevent abnormal cells from growing and dividing unchecked to form tumors. Based on this role, killin is thought to be a tumor suppressor.

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

Cowden syndrome - caused by mutations in the KLLN gene

Some cases of Cowden syndrome and a similar condition called Cowden-like syndrome result from a change involving the KLLN gene. These conditions are characterized by multiple tumor-like growths called hamartomas and an increased risk of developing certain cancers. When Cowden syndrome and Cowden-like syndrome are caused by KLLN gene mutations, the conditions are associated with a particularly high risk of developing breast and kidney cancers.

The genetic change associated with these conditions is known as promoter hypermethylation. The promoter is a region of DNA near the gene that controls gene activity (expression). Hypermethylation occurs when too many small molecules called methyl groups are attached to the promoter region. The extra methyl groups reduce the expression of the KLLN gene, which means that less killin is produced. A reduced amount of killin may allow abnormal cells to survive and proliferate inappropriately, which can lead to the formation of tumors.

The promoter region of the KLLN gene is shared with another gene, PTEN. The single promoter controls the expression of both genes. However, it appears that promoter hypermethylation only affects the expression of the KLLN gene; people with this type of genetic change have normal expression of the PTEN gene. Other types of mutations in the PTEN gene can cause Cowden syndrome and Cowden-like syndrome.

Where is the KLLN gene located?

Cytogenetic Location: 10q23

Molecular Location on chromosome 10: base pairs 89,618,917 to 89,623,193

The KLLN gene is located on the long (q) arm of chromosome 10 at position 23.

More precisely, the KLLN gene is located from base pair 89,618,917 to base pair 89,623,193 on chromosome 10.

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 KLLN?

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

Educational resources - Information pages
Human Molecular Genetics (second edition, 1999): Function of p53, the TP53 gene product (http://www.ncbi.nlm.nih.gov/books/NBK7570/)
Gene Reviews - Clinical summary (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=phts)

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

PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/pubmed?term=((KLLN%5BTIAB%5D)%20OR%20(killin%5BTIAB%5D))%20AND%20((Genes%5BMH%5D)%20OR%20(Genetic%20Phenomena%5BMH%5D))%20AND%20english%5Bla%5D%20AND%20human%5Bmh%5D)
OMIM - Genetic disorder catalog (http://omim.org/entry/612105)
Research Resources - Tools for researchers
- Atlas of Genetics and Cytogenetics in Oncology and Haematology (http://atlasgeneticsoncology.org/Genes/GC_KLLN.html)
- Entrez Gene (http://www.ncbi.nlm.nih.gov/gene/100144748)
- GeneCards (http://www.genecards.org/cgi-bin/carddisp.pl?id_type=entrezgene&id=100144748)
- HUGO Gene Nomenclature Committee (http://www.genenames.org/data/hgnc_data.php?hgnc_id=37212)

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

KILIN_HUMAN
killin

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 KLLN?

apoptosis ; cancer ; cell ; DNA ; DNA replication ; epigenetics ; gene ; hamartoma ; kidney ; methyl ; molecule ; mutation ; proliferate ; promoter ; promoter region ; protein ; syndrome ; tumor

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

References

Bennett KL, Mester J, Eng C. Germline epigenetic regulation of KILLIN in Cowden and Cowden-like syndrome. JAMA. 2010 Dec 22;304(24):2724-31. doi: 10.1001/jama.2010.1877. (http://www.ncbi.nlm.nih.gov/pubmed/21177507?dopt=Abstract)
Cho YJ, Liang P. Killin is a p53-regulated nuclear inhibitor of DNA synthesis. Proc Natl Acad Sci U S A. 2008 Apr 8;105(14):5396-401. doi: 10.1073/pnas.0705410105. Epub 2008 Apr 2. (http://www.ncbi.nlm.nih.gov/pubmed/18385383?dopt=Abstract)
Entrez Gene (http://www.ncbi.nlm.nih.gov/gene/100144748)
Jelovac D, Park BH. PTEN promoter silencing and Cowden syndrome: the role of epigenetic regulation of KILLIN. JAMA. 2010 Dec 22;304(24):2744-5. doi: 10.1001/jama.2010.1863. (http://www.ncbi.nlm.nih.gov/pubmed/21177512?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.



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