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). The gene discussed is XRCC1; the disease is Telangiectasia.