title: Frequency of 13q abnormalities among 203 patients with retinoblastoma.
abstract: We studied peripheral blood lymphocyte karyotypes of 203 patients with retinoblastoma. Twelve (5.9%) had a constitutional chromosomal abnormality involving 13q, of whom six had unilateral and six had bilateral disease. Two patients had mosaic deletions, eight had nonmosaic deletions, one had a de novo translocation, and one had a 13q14 deletion and a de novo direct insertion (10;6). Of the total, 4.9% of unilateral and 7.5% of bilateral patients had 13q abnormalities. None of 19 familial retinoblastoma patients had a visible cytogenetic abnormality. The unilateral patients with 13q abnormalities represent prezygotically determined (potentially heritable) cases which would have been classified as postzygotic (sporadic) without cytogenetic analysis. The observed 1% frequency of mosaic deletions is lower than that previously reported.
authors.affiliation: Children's Hospital of Philadelphia, PA.
authors.forename: G R
authors.initials: GR
authors.lastname: Bunin
authors.forename: B S
authors.initials: BS
authors.lastname: Emanuel
authors.forename: A T
authors.initials: AT
authors.lastname: Meadows
authors.forename: J D
authors.initials: JD
authors.lastname: Buckley
authors.forename: W G
authors.initials: WG
authors.lastname: Woods
authors.forename: G D
authors.initials: GD
authors.lastname: Hammond
mesh_terms: D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations / Q000453:epidemiology*; D002872:Chromosome Deletion; D025063:Chromosome Disorders; D002882:Chromosomes, Human, Pair 13; D005134:Eye Neoplasms / Q000235:genetics*; D005260:Female; D006801:Humans; D007621:Karyotyping; D008297:Male; D009030:Mosaicism; D012175:Retinoblastoma / Q000235:genetics*; D012737:Sex Factors