This report describes xeroderma pigmentosum, variant type (XPV), which is a subtype of xeroderma pigmentosum; XPV exhibits autosomal recessive inheritance. The human gene implicated in this disease DNA polymerase eta (POLH), which encodes a specialized DNA polymerase that more accurately replicates UV-damaged DNA. There is a single fly ortholog, PolH, for which RNAi-targeting constructs and alleles caused by insertional mutagenesis have been generated.
The human POLH gene has not been introduced into flies.
Animals homozygous for null or loss-of-function mutations of Dmel\PolH; are viable and fertile, but exhibit increased UV-sensitivity in several different assays. Physical and genetic interactions of Dmel\PolH have been described; see below and in the PolH gene report.
[updated Jul. 2017 by FlyBase; FBrf0222196]
Xeroderma pigmentosum is characterized by increased sensitivity to sunlight with the development of carcinomas at an early age. Some patients develop neurologic symptoms or a more severe clinical phenotype known as de Sanctis-Cacchione syndrome (MIM:278800) (Satokata et al., 1992; pubmed:1372102). [from MIM:278700; 2016.03.09]
Xeroderma pigmentosum (XP) is an inherited condition characterized by an extreme sensitivity to ultraviolet (UV) rays from sunlight, affecting repeatedly exposed skin and the eyes, and by a greatly increased risk of developing skin cancer. About 30 percent of people with xeroderma pigmentosum also develop progressive neurological abnormalities. [from Genetics Home Reference, Xeroderma pigmentosum; 2016.03.23]
[XERODERMA PIGMENTOSUM, VARIANT TYPE; XPV](https://omim.org/entry/278750)
[POLYMERASE, DNA, ETA; POLH](https://omim.org/entry/603968)
See general description above.
The variant form of xeroderma pigmentosum (XPV) is caused by mutations in the DNA polymerase eta gene (POLH). [from MIM:278750; 2016.03.09]
The POLH gene encodes a member of the Y family of specialized DNA polymerases. It copies undamaged DNA with a lower fidelity than other DNA-directed polymerases, however, it accurately replicates UV-damaged DNA; it plays an important role in the repair of UV-induced pyrimidine dimers. [from Gene Cards, POLH; 2016.03.23]
One to one: 1 human to 1 Drosophila.
High-scoring ortholog of human POLH (1 Drosophila to 1 human). Dmel\PolH shares 29% identity and 44% similarity with the human gene.
