title: Sporadic bilateral retinoblastoma and 13q- chromosomal deletion.
abstract: Unilateral retinoblastoma (Rb) is usually a sporadic occurrence while bilateral (multifocal) cases are often familial. Sporadic bilateral Rb associated with a long-arm deletion of a D-group chromosome has been reported in 8 children. We have studied a 6-year-old female with bilateral sporadic retinoblastoma, treated during infancy by enucleation and radiotherapy. Chromosome banding studies on peripheral lymphocytes revealed an interstitial deletion from the long arm of a chromosome 13: del(13) (q12q14). Three additional patients reported in the literature had interstitial 13q- deletions, involving slightly different though overlapping regions. The only chromosomal region consistently missing in all of these 4 cases appears to be part of the lightly staining band 13q14. We, therefore, propose this site as the precise location of a gene (or genes) involved in retinal development. Our patient lacked features of the classic 13q- or 13-ring syndrome, which involves deletion of a more distal portion of the 13 long arm. When compared to reported patients with Rb and 13q-, it became apparent that there may be a separate recognizable syndrome consisting of moderate growth and developmental delay, characteristic facies and external ears, and bilateral sporadic Rb, which is associated with an interstitial 13q- deletion.
mesh_terms: D000328:Adult; D002648:Child; D002869:Chromosome Aberrations; D002872:Chromosome Deletion; D002901:Chromosomes, Human, 13-15; D005134:Eye Neoplasms / Q000150:complications / Q000235:genetics*; D005260:Female; D005796:Genes; D006130:Growth Disorders / Q000209:etiology; D006801:Humans; D008607:Intellectual Disability / Q000209:etiology; D008297:Male; D012175:Retinoblastoma / Q000150:complications / Q000235:genetics*