These results indicate that the MMS19-XPD protein complex, now designated MMXD (MMS19-MIP18-XPD), is required for proper chromosome segregation, an abnormality of which could contribute to the pathogenesis in some cases of XP-D and XP-D/CS.
DNA repair gene polymorphisms, such as those of XRCC3 and xeroderma pigmentosum, complementation group D and G (XPD, XPG), contribute to carcinogenesis.
For the most part, the authors found no association between these genes and the cancer sites investigated, except for some statistically significant associations between XPD/ERCC2 single nucleotide polymorphisms and skin, breast, and lung cancers.
Our results indicate that SNPs in the NER genes ERCC1 (Asn118Asn, 15310G>C, 8902G>T), XPA (-4G>A), ERCC2/XPD (Lys751Gln) and ERCC5/XPD (His46His); the BER genes APE1/APEX (Ile64Val), OGG1 (Ser326Cys), PCNA (1876A>G) and XRCC1 (Arg194Trp, Arg280His, Arg399Gln); and the DSB-R genes ATR (Thr211Met), NBS1 (Glu185Gln), XRCC2 (Arg188His) and XRCC9 (Thr297Ile) modulate NSCLC risk.
DNA was extracted from blood samples and 15 common nonsynonymous SNPs in seven-nucleotide excision repair genes [XPC, RAD23B (hHR23B), CSB (ERCC6), XPD (ERCC2), CCNH, XPF (ERCC4), and XPG (ERCC5)] were genotyped.
We assessed polymorphisms in the aryl hydrocarbon receptor (AhR-Arg554Lys), null variants of the glutathione S-transferase superfamily (GSTM1 and GSTT1), x-ray repair cross-complementing 1 and 3, and Xeroderma pigmentosum, group D (XRCC1-Arg399Gln, XRCC3-Thr241Met, XPD-Lys751Gln).
We investigated the genetic basis for these findings by analysing the Asp312Asn and Lys751Gln polymorphisms of the XPD (ERCC2) DNA repair gene in the same subjects.
A photosensitive form of trichothiodystrophy (TTD) results from mutations in the same XPD gene as the DNA-repair-deficient genetic disorder xeroderma pigmentosum group D (XP-D).
Two individuals with features of both xeroderma pigmentosum and trichothiodystrophy highlight the complexity of the clinical outcomes of mutations in the XPD gene.
Two individuals with features of both xeroderma pigmentosum and trichothiodystrophy highlight the complexity of the clinical outcomes of mutations in the XPD gene.
Two individuals with features of both xeroderma pigmentosum and trichothiodystrophy highlight the complexity of the clinical outcomes of mutations in the XPD gene.
These results establish the essential function of the XPD protein in mammals and in cellular viability and are consistent with the notion that only subtle XPD mutations are found in XP, XP/Cockayne syndrome, and trichothiodystrophy patients.
In most cases, xeroderma pigmentosum group D (XP-D) and trichothiodystrophy (TTD) patients carry mutations in the carboxy-terminal domain of the evolutionarily conserved helicase XPD, which is one of the subunits of the transcription/repair factor TFIIH (refs 1,2).