The observed increased risk of telangiectasia in patients, who received an additional 15 Gy boost and/or are deficient in DNA repair owing to the inheritance of a variant XRCC1 (R399Q) allele, is consistent with the association of telangiectasia with vascular endothelial cell damage (Quarmby et al, 1999). Here, XRCC1 is linked to telangiectasis.