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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.
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.
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.
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.
You and your healthcare professional may find the following resources about KLLN helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
apoptosis ; DNA ; DNA replication ; epigenetics ; gene ; kidney ; methyl ; proliferate ; promoter ; promoter region ; protein ; syndrome ; tumor
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
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.