Novel mutation identified in the DDB2 gene in patients with xeroderma pigmentosum group–E

• Published in: International journal of dermatology 2020-08, Vol.59 (8), p.989-996
• Main Authors: Karagün, Ebru, Eroz, Recep, Gamsızkan, Mehmet, Baysak, Sevim, Eyup, Yavuz, Ozcan, Yunus
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age; Cancer; Child; Child, Preschool; Complementation; Cornea; Deoxyribonucleic acid; DNA; DNA damage; DNA-Binding Proteins - genetics; Female; Genetic analysis; Heterozygote; Homozygote; Humans; Male; Middle Aged; Mutation; Nonsense mutation; Peripheral blood; Photosensitivity; Proteins; Skin cancer; Skin Neoplasms - genetics; Squamous cell carcinoma; Xeroderma pigmentosum; Xeroderma Pigmentosum - genetics; Young Adult
• ISSN: 0011-9059; 1365-4632
• DOI: 10.1111/ijd.14957

Background Xeroderma pigmentosum (XP) is a rare photosensitive syndrome, which is divided into eight complementation groups (XP‐A to XP‐G and XPV) and characterized by skin cancers diagnosed at early age. A family of seven members (age range between 5 and 47 years) with carriers of the novel nonsense mutation that causes XP‐E type were included in the current study. Methods DNA was isolated from peripheral blood samples of the proband, and cancer predisposition genes were sequenced with next‐generation sequencing. The demographic features and the laboratory, clinical, and histopathological findings of patients were evaluated. Results In the proband, squamous cell carcinoma was first diagnosed in the right‐eye cornea at the age of 13 years and then in the left‐eye cornea at the age of 15 years. Later, the patient was diagnosed with basosquamous cell carcinoma on the dorsum of the nose at the age of 18 years. After genetic analysis, a novel nonsense c.1063C>T(p.Arg355Ter) pathogenic variation that causes XP‐E type was detected as homozygous in the DDB2 gene of the proband and her siblings, 11 and 5 years of age, and as heterozygous in her parents and a 22‐year‐old brother. Conclusion Because of the occurrence of early termination codon, truncated nonfunctional proteins or proteins with deleterious loss or gain‐of‐function activities are synthesized in nonsense mutation. Thus, to avoid the development of pathological lesions, it is important that such patients with nonsense mutation stay away from agents that might cause DNA damage and develop an appropriate lifestyle according to this condition.