Since there have been recent isolated reports of retinoblastoma associated with chromosomal defects, karyotypes were performed on 21 retinoblastoma patients (17 sporadic, 4 hereditary) in an attempt to associate a specific chromosomal abnormality with this disease. Chromosomes from a family with hereditary retinoblastoma were also studied using the new technique of scanning electron microscopy. No abnormalities were detected.
Pruett RC, Atkins L. Chromosome Studies in Patients With Retinoblastoma. Arch Ophthalmol. 1969;82(2):177-181. doi:10.1001/archopht.1969.00990020179005