Following the association in 1999 of a subset of RTS cases with homozygous or compound heterozygous mutations in the human helicase gene RECQL4 [4], two forms of RTS have emerged based on clinical and molecular analysis: type I RTS, characterised by poikiloderma, ectodermal dysplasia and juvenile cataracts, negative for the RECQL4-mutation scan and type II RTS, with poikiloderma, congenital bone defects and an increased risk of osteosarcoma related to deleterious RECQL4 mutations [5]. Here, RECQL4 is linked to osteosarcoma.