title: Genetics and cytogenetics of retinoblastoma.
abstract: Retinoblastoma tumor formation is initiated by loss of function of both alleles at the RB1 locus on chromosome 13. In nonhereditary retinoblastoma (60% of patients), both mutations occur during retinal development. In hereditary retinoblastoma (40% of patients), tumor formation is caused by one germline and one somatic mutation. The RB1 gene encodes a nuclear protein that arrests progression through the G1 phase of the cell cycle. In the absence of intact RB1 protein, unscheduled cell proliferation occurs. Genes on chromosomes 1 and 6, which have not yet been identified, appear to be involved in later stages of tumorigenesis.
authors.affiliation: Institut für Humangenetik, Universitätsklinikum Essen, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Horsthemke
mesh_terms: D002882:Chromosomes, Human, Pair 13; D005134:Eye Neoplasms / Q000235:genetics*; D016161:Genes, Retinoblastoma / Q000502:physiology; D006801:Humans; D007621:Karyotyping; D009154:Mutation; D015183:Restriction Mapping; D012175:Retinoblastoma / Q000235:genetics*