Table 1.
Genetic alterations associated with XP (modified from Kraemer et al. [3])
| Gene | Molecular pathway | Proportion | Phenotype | Geography |
|---|---|---|---|---|
| XPA | Common repair pathway | 25% | XP with mild-to-severe neurologic abnormalities | Common in Japan, rare in the US and Europe |
| ERCC3 (XPB) | Common repair pathway | Rare | XP/CS TTD XP with mild neurologic abnormalities | |
| XPC | GGR | 25% | Nonneurologic | |
| ERCC2 (XPD) | GGR/TCR (at the junction) | 15% | Complex manifestations (XP, CS, XP/CS, XP/TTD, COFS) | |
| DDB2 (XPE) | GGR | Rare | Nonneurologic | |
| ERCC4 (XPF) | Common repair pathway | 6% | Nonneurologic abnormalities, or late-onset severe neurologic abnormalities | |
| ERCC5 (XPG) | Common repair pathway | 6% | CS XP/CS | |
| ERCC1 | Common repair pathway | Rare | COFS | One patient reported (born to nonconsanguineous white Italian parents) [6] |
| POLH (XPV) | Technically, a polymerase not part of NER | 21% | XP with no neurologic abnormalities | |
TTD = Trichothiodystrophy; COFS = cerebro-oculo-facio-skeletal.