[Clinical research of genetic counseling].

To supply reliable materials for the assessment of recurrence risk,prenatal diagnosis and the supervision of high risk persons,we analyzed 10811 patients with the methods of cytogenetics,fluorescent in situ hybridization and molecular genetic PCR methods. The result of cytogenetics:there were 555 abnormal karyotypes of peripheral blood on 5390 cases (10.30%);In 2171 patients who asked for prenatal diagnosis,145 abnormal karyotypes were found (6.68%);We also karyotyped chorionic villous cells of 62 patients with spontaneous abortion and found 28 abnormal karyotypes (45.16%). The PCR results of 23 patients with Down's syndrome were all positive while the results of 155 normal persons were all negative. The method of cytogenetics is very important for diagnosis of abnormal karyotypes;Molecular genetic methods by PCR and FISH are quick,convenient and applicable way.