Cytogenetic and molecular genetic analysis of Down's Syndrome-287 cases / 重庆医科大学学报

ABSTRACT

Objective:To better understand the karyotype distribution ofthe patients with Down's syndrome(DS)who have been finally diagnosed in our hospital.To compare the strengths of G-banding karyotype analysis and FISH(Fluorescence In Situ Hybridization, FISH)in diagnosing the DS patients with the Chromosome mosaicism and Calculating the percentage of abnormal karyotypes.Methods:Blood of the patients who were likely to suffer from DS was selected for G-banding karyotype analysis to describe the karyotype distribution.5 of the finally diagnosed patients with the chromosome mosaicism were randomly selected for FISH to compare the percentage of abnormal karyotypes of the two methods.Results:287 DS patients were diagnosed,91.29%of whom had the simple karyotype.Among the patients with the translocation karyotype, 11 D/G translocation karyotype were detected,accounting for 73.33%,while 4 G/G translocation karyotype were diagnosed, constituting 26.67%.One patient with both of the translocation karyotype and the mosaicism karyotype was detected in our research,which was uncommon in recent report.The results of FISH and G-banding karyotype analysis were consistent.There was no significant difference of the abnormal karyotype rates for DS patients with the chromosome mosaicism by G-banding karyotype analysis and FISH.Conclusion:The simple karyotype is the main karyotype of the DS patients in our research.Among the translocation karyotype,the D/G kind is common.DS patients can be diagnosed efficiently by G-banding karyotype analysis,but we still suggest to use FISH to get the proportion of the abnormal cell for the patients who have less triploid cell and slighter clinical manifestation.