Today Down's syndrome is recognizable on the basis of its clinical c haracteristics in infants. According to present knowledge, Down's syndr ome can be classified cytogenetically into 4 groups: regular trisomy, translocational trisomy, mosaic forms and double trisomies. Knowledge of the karyotype is used in genetic counselling for further prevention of Down's syndrome in unborn fetuses. Prenatal chromosome analyses, a form of intrauterine diagnosis, has been used in Hungary since 1968. The average incidence of Down's syndrome has been estimated at 1.5:1000 among newborns. The mother's age and genetic deviations are determinant s in whether or not the syndrome will occur. The risk of Down's syndrome increases from 1 per 1000 in mothers under 30 to 10-20 per 1000 in mothers over 45. Since risk increases with the mother's age amniocen tesis should be routinely performed in pregnancies of older mothers. In the case of trisomy verified by intrauterine diagnosis, termination of pregnancy is advised. If population cytogenetic investigations are practiced, the carriers of the balanced translocation will be revealed and within a few years there will be only 3 indications for amniocentesis: 1) in cases of mother's advanced age, 2) in cases of bala nced translocation carrier and 3) in cases of a previously affected chil d disregarding the parental karyotypes. The expected risk of Down's syn drome predictable from available data if higher than 1-5% justifies intr auterine chromosome analysis.
|Number of pages||6|
|Journal||Medical gynaecology, andrology, and sociology|
|Publication status||Published - Dec 1 1973|
ASJC Scopus subject areas