Molecular Diagnosis of Genic Abnormalities using Human Tissue Materials

1)用DXZ1和DYZ1(Oncor)两种DNA探针对人胚胎和胎儿组织石蜡切片进行了荧光原位杂交(FISH)研究。本研究中检测的人胚胎和胎儿组织的石蜡切片在4%多聚甲醛中固定后，在室温下保存了长达5年。3个胚胎和4个胎儿的细胞分别与DXZ1和DYZ1探针杂交信号阳性，均为男性。其余4个胚胎和1个胎儿的细胞与DXZ1探针在一个核内有两个相同的杂交信号，而不是没有与DYZ1杂交的信号，这表明它们的细胞有两个X染色体，但没有Y染色体。检查的5个胎儿的FISH结果与其生殖器性别和/或性腺组织学相一致。因此，FISH技术已被证明可以在石蜡切片上原位显示特定的DNA，并有助于确定固定的胚胎和胎儿的性别。2)对中和福尔马林固定的45，X核型胎儿的组织进行了FISH研究。FISH与其组织的杂交结果显示，每个细胞的细胞核与DXZ1探针有一个杂交信号，而与DYZ1探针完全没有杂交信号，表明胎儿的性染色体的构成是XO。本结果表明，在有固定组织或石蜡切片的情况下，用染色体特异性DNA探针回溯鉴定染色体非整倍体是可行的。

1) A fluorescent in situ hybridization (FISH) study was carried out on paraffin sections of human embryonic and fetal tissues with two DNA probes, DXZ1 and DYZ1 (Oncor), for X and Y chromosome-specific DNA sequences, respectively. The paraffin blocks of the human embryonic and fetal tissues examined in the present study had been stored at room temperature for up to 5 years after fixation in 4% paraformaldehyde. All the 7 embryos and 5 fetuses examined were successfully sexed by FISH.The cells from 3 embryos and 4 fetuses were positive for a hybridization signal with each of the DXZ1 and DYZ1 probes and they were classified as male. The cells from the remaining 4 embryos and 1 fetus were positive for two identical hybridization signals with DXZ1 probe in a nucleus instead of the absence of the signal hybridized with DYZ1, indicating that their cells have two X chromosomes but no Y chromosomes. The FISH results for the 5 fetuses examined were consistent with their genital sex and/or gonadal histology. Thus, the FISH technique has been shown to visualize specific DNAs in situ on paraffin sections and to be useful to determine the sex of fixed embryos and fetuses retrospectively.2) A FISH study was carried out on paraffin sections of tissues from fetuses with 45, X karyotype which had been fixed in neutralized formalin. The results of the FISH with their tissues showed that the nucleus of each cell had one hybridization signal with the DXZ1 probe but was entirely negative for signals with the DYZ1 probe, indicating that the constitution of sex chromosomes of the fetuses was XO.The present results showed it feasible to retrospectively identify chromosome aneuploidies by FISH with chromosome-specific DNA probes if fixed tissues or paraffin blocks are available.