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Xeroderma Pigmentosum in Brazil – defining clinical profile and mutational spectrum in an admixed population

Wednesday, September 13, 2017 — Poster Session II

3:30 p.m. – 5:00 p.m.
FAES Terrace
NCI
GEN-9

Authors

  • KM Santiago
  • LP Castro
  • SR Rogatto
  • JPD Neto
  • P Ashton-Prolla
  • PFV Medeiros
  • EM Ribeiro
  • BF Rodrigues
  • FF Valle
  • MJR Doriqui
  • CHB Leite
  • LMS Moura
  • V Munford
  • CFM Menck
  • MIW Achatz

Abstract

Xeroderma Pigmentosum (XP) syndrome is an autosomal recessive disease linked to germline biallelic mutations in genes from the nucleotide excision repair or translesion synthesis pathways and associated with an increase in risk of developing skin tumors due to damaging effects of ultraviolet radiation. Beyonnnd the recent comprehensive description of a Brazilian region, named Araras, with the densest known area of XP patients, the molecular pattern of XP syndrome widespread in this tropical country is unknown. The aim of this study was to analyze the clinical profile and molecular diagnosis of XP Brazilian cases from distinct Brazilian regions. We investigated the XPA, ERCC3/XPB, XPC, ERCC2/XPD, DDB2/XPE, ERCC4/XPF, ERCC5/XPG and POLH/XPV genes by Sanger or targeted exome sequencing searching for germiline variants in blood or saliva samples from 28 families. Pathogenic or likely pathogenic variants were detected in all index cases occurring in the XPA (1), XPC (17), ERCC2/XPD (1), DDB2/XPE (1), ERCC5/XPG (1) and POLH/XPV (7) genes, including nine novel mutations. One mutation in POLH/XPV and six in XPC were found in more than one unrelated family, including the XPC:c.2251-1G>C found in a high frequency (10 cases) and previously identified in the Comorian Islands. Clinical presentation does not differ from those in different countries, with exception of POLH/XPV cases that presented the first clinical manifestation earlier. This study identified the XPC and POLH/XPV as the predominantly mutated genes and brought the first report of a XPA Brazilian case, contributing to the knowledge of mutational spectrum of XP in the Brazilian population.

Category: Genetics and Genomics