Analysis of polymorphisms of the vitamin D receptor, estrogen receptor, and collagen Ialpha1 genes and their relationship with height in children with bone cancer. The authors' objectives were to compare height at diagnosis of children with bone tumors with that of Spanish reference children; to analyze the frequency of the genotypes for the polymorphisms of the vitamin D receptor (VDR), estrogen receptor (ER), and collagen Ialpha1 (COLIalpha1) genes in patients and in healthy controls; and to test the relationship between the genetic markers and height.Height and weight at diagnosis were measured in 58 osteosarcoma and 36 Ewing sarcoma patients and compared with standards published for Spanish reference children according to sex and age. For the molecular analysis, genetic polymorphisms of the VDR (Fok I, Apa I, and TaqI), ER (Pvu II and XbaI), and COLIalpha1 (Msc I) genes were characterized in 72 osteosarcoma and 53 Ewing sarcomas and in a group of 143 healthy matched children.Osteosarcoma and Ewing sarcoma patients were significantly taller than Spanish reference children. Osteosarcoma patients showed a significantly higher frequency of the Ff genotype for the Fok I polymorphism (VDR gene) than the control group. The odds ratio for this genotype was 1.78, with an increased relative risk of 78% for heterozygous Ff carriers. Among Ewing sarcoma patients, this same genotype was significantly associated with lower height than homozygotes (FF or ff).Children with bone cancer are significantly taller than the reference population, which may be influenced by the genotype for the Fok I polymorphism of the VDR gene.