Table 1.
Genes involved in xeroderma pigmentosum, Cockayne’s syndrome and trichothiodystrophy.
| Gene | Genomic Location/Size | Coding Sequence Size (bp) | Clinical Manifestation | UV-Sensitivity | Residual DNA Repair | Relative Frequency | Skin Cancer | Neurological Implications |
|---|---|---|---|---|---|---|---|---|
| Global Genome Repair | ||||||||
| XPC | 3p25 | 3558 | XP | ++ | <10%–30% | High | + | − |
| DDB1 | 11q12–q13 | 3420 | N/A | N/A | N/A | N/A | N/A | N/A |
| DDB2 (XPE) | 11p12–p11 | 4193 | XP | + | 50% | Rare | + | − |
| Transcription Coupled Repair | ||||||||
| CSA | 5q12.1 | 2011 | CS | + | Normal | Intermediate | − | ++ |
| CSB | 10q11.21 | 4714 | CS | + | Normal | High | − | ++ |
| Nucleotide Excision Repair | ||||||||
| XPA | 9q22.3 | 1377 | XP | +++ | <5% | High | + | ++ |
| XPB | 2q14.3 | 2751 | XP, XP/CS, TTD | ++ | 3%–40% | Rare | +/− | + |
| XPD | 19q13.3 | 2400 | XP, XP/CS, TTD | ++ | 15%–50% | Intermediate | + | ++/− |
| XPF | 16p13.1 | 2881 | XP | + | 15%–30% | Rare | + | −/+ |
| XPG | 13q33.1 | 4091 | XP, XP/CS | ++ | <5%–30% | Rare | + | ++ |
| ERCC1 | 19q13.3–q13.2 | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| TTD-A | 6p25.3 | 7503 | TTD | N/A | Rare | − | ++ | |
| Translesion Synthesis | ||||||||
| DN/A PolH (XPV) | 6p21.1 | 2140 | XP | − | Normal | High | +/− | − |
XP: Xeroderma Pigmentosum; CS, Cockayne’s syndrome; TTD: trichothyodystrophy; N/A = not applicable, + = mild, ++ = moderate, +++ = severe and − = not present.