| OBJECTIVE: Spontaneous abortion is one of the most severe complications of clinical recognized pregnancies. The clinical and epidemiological data indicated that the genetic abnormalities played an important role in early pregnancy loss. Up to present conventional cytogenetic analysis performed on pregnancy-loss tissues is the primary tool available for chromosomal abnormalities, but the limitation of cytogenetic analysis has been recognized which can lead to low diagnosis rate. In this series, we applied comparative genomic hybridization (CGH) to analyze 38 pregnancy-loss tissues. We compared the result of CGH analysis with the conventional cytogenetic method (karytype analysis), so as to establish molecular cytogenetic method to diagnose the sample from spontaneous aborted embryoes.METHODS: 38 patients who suffered from spontaneous abortion were observed. The pregnant periods were between 49 and 91 days. in the condition of sterilization, villi of fetal withered samples were picked from vagina, among these there were 27 fresh aborted samples and 11 old aborted samples. One part of villi was detected by villus culture and chromosome karytype analysis, the other part was detected by comparative genomic hybridization. Regions of gain or loss of DNA sequences were observed as changes in the ratio of the intensities of the two fluorochromes along the chromosome target. 0.8 and 1.2 were chosen as thresholds for the identification of DNA copy number decreases (below 0.8) and increases (above 1.2) respectively. RESULT All samples from 38 spontaneous abortion are diagnosed by CGH method,whereas only 31 present the results with conventional cytogenetic karytype analysis. Among these, 90% results of CGH and conventional cytogenetic analysis are identical. In the other 7 cases in whom we failed to culture the trophoblast cells, we find 3 chromosome abnormalities by CGH.CONCLUSION: Comparative genomic hybridization is helpful to analyse the spontaneous abortion sample.
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