视网膜母细胞瘤为儿童期的肿瘤,其发病率为1:20,000。它高发于具有两种遗传素质的个体,即由遗传承受了常染色体显性样肿瘤发病倾向者和生来即有13号染色体长臂部份缺失者。后一种尤其重要之处在于,它是在人类唯一已知可见于合子前的特异的染色体缺陷,同时又恒定地导致某一特定肿瘤发病倾向的例子。本文报告了两名视网膜母细胞瘤患者的病例和细胞遗传学检查结果。由于用G—显 Retinoblastoma is a childhood tumor with an incidence of 1:20,000. It is prevalent in individuals with two genetic qualities, that is, individuals who have inherited autosomal dominant tumor tendencies and are born with a missing long arm of chromosome 13. The latter is particularly important in that it is the only case in humans where specific chromosomal defects are known to be found before the zygote, while at the same time constantly leading to the predisposition to a particular tumor. This article reports the results of two cases of retinoblastoma patients and cytogenetics. Due to G-significant