Murthy D S, Murthy S K, Patel J K, Tyagi A A
Indian J Exp Biol. 1989 Oct;27(10):864-7.
An unusual nucleolar organizer region (double NOR) on chromosome 13 was observed in a Down syndrome child [47, XY, +21, dNOR(13)]. The variant chromosome was inherited from the mother [46, XX, dNOR(13)]. The extra chromosome 21 in the proband was maternal origin. The frequency of NOR chromosome association showed relatively high frequency in the mother and proband as compared to the controls. The result suggest that chromosome variants involving extra copies of NOR may indeed be involved in the meiotic nondisjunction of chromosome-21.
在一名唐氏综合征患儿[47, XY, +21, dNOR(13)]中观察到13号染色体上存在一个不寻常的核仁组织区（双NOR）。这条变异染色体遗传自母亲[46, XX, dNOR(13)]。先证者额外的21号染色体来自母亲。与对照组相比，母亲和先证者中NOR染色体联会的频率相对较高。结果表明，涉及NOR额外拷贝的染色体变异可能确实与21号染色体的减数分裂不分离有关。
