Editing DNA ligase (section)

== Disorders ==
Genetic deficiencies in human DNA ligases have been associated with clinical syndromes marked by immunodeficiency, radiation sensitivity, and developmental abnormalities,&nbsp;<ref name="Shuman 17365–17369"/> [[LIG4 syndrome]] (Ligase IV syndrome) is a rare disease associated with mutations in DNA ligase 4 and interferes with dsDNA break-repair mechanisms. Ligase IV syndrome causes immunodeficiency in individuals and is commonly associated with microcephaly and marrow hypoplasia.<ref>{{cite journal | vauthors = Altmann T, Gennery AR | title = DNA ligase IV syndrome; a review | journal = Orphanet Journal of Rare Diseases | volume = 11 | issue = 1 | pages = 137 | date = October 2016 | pmid = 27717373 | pmc = 5055698 | doi = 10.1186/s13023-016-0520-1 | doi-access = free }}</ref> A list of prevalent diseases caused by lack of or malfunctioning of DNA ligase is as follows.

=== Xeroderma pigmentosum ===

[[Xeroderma pigmentosum]], which is commonly known as XP, is an inherited condition characterized by an extreme sensitivity to ultraviolet (UV) rays from sunlight. This condition mostly affects the eyes and areas of skin exposed to the sun. Some affected individuals also have problems involving the nervous system.<ref>{{Cite web|url=https://ghr.nlm.nih.gov/condition/xeroderma-pigmentosum|title=xeroderma pigmentosum| work = Genetics Home Reference | access-date = 2017-05-15 }}</ref>

=== Ataxia-telangiectasia ===

Mutations in the&nbsp;ATM&nbsp;gene cause&nbsp;[[ataxia–telangiectasia]]. The&nbsp;ATM&nbsp;gene provides instructions for making a protein that helps control&nbsp;cell&nbsp;division&nbsp;and is involved in DNA repair. This protein plays an important role in the normal development and activity of several body systems, including the nervous system and immune system. The ATM protein assists cells in recognizing damaged or broken DNA strands and coordinates DNA repair by activating enzymes that fix the broken strands. Efficient repair of damaged DNA strands helps maintain the stability of the cell's genetic information. Affected children typically develop difficulty walking, problems with balance and hand coordination, involuntary jerking movements (chorea), muscle twitches (myoclonus), and disturbances in nerve function (neuropathy). The movement problems typically cause people to require wheelchair assistance by adolescence. People with this disorder also have slurred speech and trouble moving their eyes to look side-to-side (oculomotor apraxia).<ref>{{cite web | url = https://ghr.nlm.nih.gov/condition/ataxia-telangiectasia#genes | title = ataxia-telangiectasia | work = Genetics Home Reference | access-date = 2017-05-15 }}</ref>

=== Fanconi Anemia ===

[[Fanconi anemia]] (FA) is a rare, inherited blood disorder that leads to bone marrow failure. FA prevents bone marrow from making enough new blood cells for the body to work normally. FA also can cause the bone marrow to make many faulty blood cells. This can lead to serious health problems, such as [[leukemia]].<ref>{{cite web | url = https://www.nhlbi.nih.gov/health/health-topics/topics/fanconi | title = What Is Fanconi Anemia? | publisher = NHLBI, NIH | access-date = 2017-05-15 }}</ref>

=== Bloom syndrome ===

[[Bloom syndrome]] results in skin that is sensitive to sun exposure, and usually the development of a butterfly-shaped patch of reddened skin across the nose and cheeks. A skin rash can also appear on other areas that are typically exposed to the sun, such as the back of the hands and the forearms. Small clusters of enlarged blood vessels (telangiectases) often appear in the rash; telangiectases can also occur in the eyes. Other skin features include patches of skin that are lighter or darker than the surrounding areas (hypopigmentation or hyperpigmentation respectively). These patches appear on areas of the skin that are not exposed to the sun, and their development is not related to the rashes.