Genotypes and Phenotypes of Uygur Children With Xeroderma Pigmentosum: A Case Study in Xinjiang, China

Abstract

Objective: Xeroderma pigmentosum (XP) is a rare autosomal recessive dermatosis caused by genetic defects of DNA repair. This study was performed to detect and analyze the genes of 2 Uygur patients with XP and their families and assess the patients’ phenotypes, which may enrich the understanding of the genetic skin disorder spectrum in Xinjiang area. Methods: We collected the clinical data from 2 patients with XP and peripheral blood samples from the patients and their family members. The patients’ DNA was sequenced and detected by Sanger sequencing, and gene mutations were screened. Results: The proband in family 1 presented with brown maculae at the exposure site and squamous cell carcinoma secondary to a facial rash. The proband had a homozygous nucleotide variation of XPC c.2251-2A> G (A change from A to G in the penultimate position of the intron before the 2251 position in the coding region), which was a shear mutation. In this family, both parents were heterozygous, and no similar mutation detected in the sister. In family 2, the proband had scattered black brown spots and papules on the trunk and limbs. and his younger sister was also a patient. The proband and his younger sister had homonucleotide variation of XPA c.631C> T, which was nonsense mutation, resulting in the codon for Arg No.211 being changed into termination codon (p.arg211X), thus terminating the peptide chain synthesis prematurely. All the normal individuals in the two families were heterozygotes, and homozygous mutations occurred in all the patients, which was consistent with the autosomal recessive inheritance. Conclusion: XP is rare in Uygur population. This study expanded the mutation spectrum of XP and provided a basis for early diagnosis, treatment, prognostic prediction, and prenatal genetic consultation.