Background:
To investigate the current status of chromosomal aberrations of Down syndrome in Korea between 1982 and 1994.
Methods:
We studied 1,108 cytogenetic data of Down syndrome: 154 from Department of Clinical Pathology, Keimyung University, School of Medicine, in which cytogenetic studies were carried out by G-banded metaphase from peripheral blood of 1,826 patients
with
suspected genetic disease between March 1991 and Augst 1994, and 954 from the literatures reported in Korea between 1982 and 1993.
Results:
Among 1,826 cases studied in Kemyung University, chromosomal aberrations were detected in 318 cases(17.2%), and 21 trisomies were 154 cases(8.4%), which comprised 48.4% of chromosomal aberration and 66.4% of autosomal aberration and it was
further
classified as that 139(90/3%) were classic, two(1.3%) were mosaic, 10(6.5%) were Robertsonian translocation[five t(14q;21q) and five t (21q;21q)], three were variants. In 21 trisomy studied in Keimying University, sex ratio(M:F) was 1.43 and
almost
cases were classed below one years old, and mean maternal age at the time of delivery of Down infant with classic karyotype was 30.8 years old, and in the case with structural abnormality it was 28.6% years old. Among 1,108 cases of 21 trisomies
in
Korea, 958(86.5%) were classic, 48(4.3%) were mosaic, 92(8.3%) were Robertsonian translocation and 10(0.9%) were variant. Among 92 Robertsonian translocation, 50(54.3%) were t(14q;21q), 38(41.3%) were (21q; 21q) and each 2 cases of t(15q;21q) and
t921q;22q) were examined. Among 5 Robertsolnian translocation in which family-study could be performed, 4 cases of mother of Down syndrome were carrier.
Conclusion:
Robersonian translocation was present in high incidence as 8.3% of Down syndrome in Korea but the effort for the family study with cytogenetic analysis and genetic counselling was minimal.
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