Clinical and Cytogenetic study on 3,672 Genetic Amniocentesis: YUMC 20 years experience from 1985 to 2004 years

Yang, Young Ho; Yang, Eun Suk; Park, Yong Won; Kim, Sei Kwang; Kim, In Kyu; Son, Yong Seok

Abstract

OBJECTIVE
To systematic analyze the change of the annual distribution and indications, age distribution of the patients and chromosomal results according to patient's age and indications in midtrimester genetic amniocentesis
METHODS
This study conducted between 1985 and 2004 collected 3,672 amniocenteses procedure which were done at College of Medicine, after prenatal genetic counceling for mothers who have high risk for carrying chromosomally abnormal babies.
RESULTS
1. The incidence of amniocentesis had been in gradual increase since the 1980''s, however, the number has increased sharply for the patiences in mid 1990's. 2. Of the 3,672 amniocentesis cases, 32.2% was maternal age 30 to 34 which was most common age group and followed by age 35 to 39 was 29.9% and age 25 to 29 was 27.8%. 3. The indications for amniocentesis were advanced maternal age (36.1%), abnormal maternal serum markers (31.7%) and abnormal ultrasonographic findings which implies chromosomal abnormality (9.6%). In the 1980's, amniocentesis had earlier been used primarily for those in advanced maternal age groups, at least 35 years older. Recently maternal serum markers and ultrasonography play an important role as an indicator for the amniocentesis. 4. From the 3,672 cases, 3,556 cases showed normal diploidy and 116 cases abnormal karyotype which consisted 3.16%. In autosomal disorders, 36 Down syndrome, 15 Edward syndrome, 2 Patau syndrome were diagnosed. In Sex chromosomal anomaly, 5 Turner syndrome, 6 47XYY, and 2 Klinefelter syndrome. Add to that 31 translocation including 21 Reciprocal translocation and 10 Robertsonian translocation, and 8 deletions and 4 mosaicisms were diagnosed. Of the 354 cases with abnormal ultrasonic findings, 19 (5.4%) resulted in chromosomal anomaly. Of the 1,164 casaes with positive maternal serum markers, 42 (3.6%) resulted in chromosomal anomaly. Those who had abnormal ultrasonographic findings implying chromosomal abnormality were found to have correlation with chromosomal abnomality than other indications.
CONCLUSION
Midtrimester genetic amniocentesis is an important diagnostic tool in prenatal diagnosis, of which the annual incidence has been recently increased abruptly. Not only maternal age, but the maternal serum markers and ultrasonograms should be considered in prenatal counseling. Amniocentesis should be well informed to the general population.