Chromosome deletion in a case of retinoblastoma

SUMMARY In the course of an investigation of karyotypes in patients with retinoblastoma, one was found in whom all cells showed a deletion in the longer arm of one of the large acrocentric chromosomes. Five other patients had normal karyotypes. The writers wish to thank Dr White Franklin for drawing attention to case no. 1 and arranging for the biopsy, Dr Joy D. A. Delhanty for the fibroblast culture in case no. 1, Dr R. G. Chitham for the culture in case no. 6, Dr Sylvia D. Lawler for suggestions and Miss Dorothy Newlyn for family history investigations. The work was carried out with the aid of a grant RG‐6984 from the United States Public Health Service.