Editing Chromosomal translocation (section)

== Role in Disease ==
Chromosomal translocations can cause a diverse array of diseases, mutations or other heritable changes within an individuals genomes. Often, these mutations are caused by the loss of genetic information resulting from a structural change in the chromosome. There are three main forms of structural changes, and each of these has a role within the creation of disease. Whether it be from the structural changes themselves, or directly from the loss of genetic information, many varying diseases or mutations can be acquired due to chromosomal translocations.

A prevalent and dangerous disease resulting from chromosomal translocations is Cancer.<ref>{{Cite web |title=Cancer - Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/cancer/symptoms-causes/syc-20370588#:~:text=Cancer%20refers%20to%20any%20one,of%20death%20in%20the%20world |access-date=2025-04-11 |website=Mayo Clinic |language=en}}</ref> There are several forms of cancer that are caused by acquired translocations, many of them falling within the classifications of leukemia,<ref>{{Cite web |title=Leukemia—Patient Version - NCI |url=https://www.cancer.gov/types/leukemia#:~:text=Leukemia%20is%20a%20broad%20term,in%20children%20younger%20than%2015 |access-date=2025-04-11 |website=www.cancer.gov |language=en}}</ref> acute myelogenous leukemia,<ref>{{Cite web |date=2025-04-04 |title=Acute Myeloid Leukemia Treatment - NCI |url=https://www.cancer.gov/types/leukemia/patient/adult-aml-treatment-pdq#:~:text=and%20treatment%20options.-,Adult%20acute%20myeloid%20leukemia%20(AML)%20is%20a%20type%20of%20cancer,if%20it%20is%20not%20treated. |access-date=2025-04-11 |website=www.cancer.gov |language=en}}</ref> and chronic myelogenous leukemia,<ref>{{Cite web |title=Chronic myelogenous leukemia - Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/chronic-myelogenous-leukemia/symptoms-causes/syc-20352417 |access-date=2025-04-11 |website=Mayo Clinic |language=en}}</ref> with additional translation classifications being detected within solid malignancies such as Ewing's sarcoma.<ref>{{Cite web |title=Ewing sarcoma - Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/ewing-sarcoma/symptoms-causes/syc-20351071#:~:text=Ewing%20sarcoma%20is%20a%20type,can%20happen%20in%20any%20bone. |access-date=2025-04-11 |website=Mayo Clinic |language=en}}</ref> Regardless of the cancer classification, the most common process for generation of these cancers is through the disruption or misregulation of normal gene function. This results in the molecular rearrangement of the genes necessary for proper gene regulation, therefore resulting in cancer formation.<ref name=":15">{{Cite web |title=Human Chromosome Translocations and Cancer {{!}} Learn Science at Scitable |url=https://www.nature.com/scitable/topicpage/human-chromosome-translocations-and-cancer-23487/ |access-date=2025-04-02 |website=www.nature.com |language=en}}</ref> An alternative way that such cancers can be formed is through the fusion of coding sequences. This fusion results from the translation forcing the generation of a ring or iso chromosome, or from DNA end joining due to a close proximity between homologues genes, therefore creating a potent, fused oncogene.<ref>{{cite journal |last1=Streb |first1=Patrick |last2=Kowarz |first2=Eric |last3=Benz |first3=Tamara |last4=Reis |first4=Jennifer |last5=Marschalek |first5=Rolf |title=How chromosomal translocations arise to cause cancer: Gene proximity, trans-splicing, and DNA end joining |journal=iScience |date=June 2023 |volume=26 |issue=6 |pages=106900 |doi=10.1016/j.isci.2023.106900 |pmid=37378346 |pmc=10291325 |bibcode=2023iSci...26j6900S }}</ref><ref>{{Cite journal |last=Aplan |first=Peter D. |date=January 2006 |title=Causes of oncogenic chromosomal translocation |journal=Trends in Genetics |volume=22 |issue=1 |pages=46–55 |doi=10.1016/j.tig.2005.10.002 |issn=0168-9525 |pmc=1762911 |pmid=16257470}}</ref>

Infertility is also a prevalent and common form of disease that is generated by chromosomal translocations, and often can be asymptomatic or symptomatic within fetuses.<ref>{{Cite web |title=Infertility |url=https://www.who.int/news-room/fact-sheets/detail/infertility#:~:text=Infertility%20is%20a%20disease%20of,male,%20female%20or%20unexplained%20factors. |access-date=2025-04-11 |website=www.who.int |language=en}}</ref> Commonly influenced by one of the parents being a carrier for a balanced translocation yet being asymptomatic, the offspring often acquire additional mutations prior to birth resulting in the effect and symptomatic response due to the presence of the translocation within their genome. Ultimately, this symptomatic response is discovered when homology between two individuals genomes results in the loss of genetic information from the asymptomatic chromosomal translocation becoming problematic.<ref name=":15" /><ref>{{Cite journal |last1=Zhang |first1=Hong-Guo |last2=Wang |first2=Rui-Xue |last3=Pan |first3=Yuan |last4=Zhang |first4=Han |last5=Li |first5=Lei-Lei |last6=Zhu |first6=Hai-Bo |last7=Liu |first7=Rui-Zhi |date=2018-01-25 |title=A report of nine cases and review of the literature of infertile men carrying balanced translocations involving chromosome 5 |journal=Molecular Cytogenetics |volume=11 |issue=1 |pages=10 |doi=10.1186/s13039-018-0360-x |doi-access=free |pmid=29416565 |issn=1755-8166|pmc=5785882 }}</ref>

In addition, the inheritance of Down syndrome<ref>{{Cite web |last=CDC |date=2024-12-26 |title=Down Syndrome |url=https://www.cdc.gov/birth-defects/about/down-syndrome.html#:~:text=Down%20syndrome%20is%20a%20condition,their%20body%20and%20brain%20develop |access-date=2025-04-11 |website=Birth Defects |language=en-us}}</ref> can be caused by chromosomal translocations. In a minority (approximately 3 - 4%) of Down syndrome syndrome cases, the cause for this mutation is that of a Robertsonian translocation of chromosomes. This results from the Robertsonian translocation of the chromosome 21 long arm, onto the long arm of chromosome 14.<ref name=":16">{{Cite web |last=Philadelphia |first=The Children's Hospital of |title=Translocation Down Syndrome {{!}} Children's Hospital of Philadelphia |url=https://www.chop.edu/conditions-diseases/translocation-down-syndrome |access-date=2025-04-02 |website=www.chop.edu |language=en}}</ref> These translocations can also occur onto other chromsomes, such as chromosome 13, 15, or 22 resulting in these chromosomes also being referred to as Robertsonian chromosomes. Regardless of where, the result is a loss of information on chromosome 21 genes, and an addition of genetic information on the altering chromosome.<ref name=":16" />

Finally, chromosomal translocations between the sex chromosomes can also result in a number of genetic conditions, such as [[XX male syndrome]],<ref>{{cite book |last1=Gilbert |first1=Scott F. |title=Developmental Biology. 6th edition |date=2000 |publisher=Sinauer Associates |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK9967/ |chapter=Chromosomal Sex Determination in Mammals }}</ref> which is caused by a translocation of the SRY gene from the Y to the X chromosome.<ref>{{Cite web |title=SRY gene |url=https://medlineplus.gov/download/genetics/gene/sry.pdf |website=medlineplus.gov}}</ref> Alternatively, additional genetic diseases can also be a result of chromosomal translocations, such as Emmanuel syndrome,<ref>{{cite web | url=https://medlineplus.gov/genetics/condition/emanuel-syndrome/ | title=Emanuel syndrome: MedlinePlus Genetics }}</ref> Klinfelter syndrome<ref>{{cite journal |last1=Gaviria |first1=Anibal |last2=Cadena-Ullauri |first2=Santiago |last3=Cevallos |first3=Francisco |last4=Guevara-Ramirez |first4=Patricia |last5=Ruiz-Pozo |first5=Viviana |last6=Tamayo-Trujillo |first6=Rafael |last7=Paz-Cruz |first7=Elius |last8=Zambrano |first8=Ana Karina |title=Clinical, cytogenetic, and genomic analyses of an Ecuadorian subject with Klinefelter syndrome, recessive hemophilia A, and 1;19 chromosomal translocation: a case report |journal=Molecular Cytogenetics |date=5 September 2022 |volume=15 |issue=1 |pages=40 |doi=10.1186/s13039-022-00618-w |doi-access=free |pmid=36064723 |pmc=9446752 }}</ref> and Turner syndrome.<ref>{{cite web | url=https://www.mayoclinic.org/diseases-conditions/turner-syndrome/symptoms-causes/syc-20360782 | title=A genetic disorder that affects females-Turner syndrome - Symptoms & causes | website=[[Mayo Clinic]] }}</ref>