Diagnosing of chromosome abnormalities in Denmark.

A survey of how frequent chromosome abnormalities are diagnosed in Denmark prenatally as well as postnatally compared with the expected incidence in an 11-year period 1970-1980 has been made from the Danish Cytogenetic Central Register. Ten percent of the expected number of Klinefelter's syndrome, 41% of Turner's syndrome and 10% of other sex chromosome abnormalities in children born between 1970 and 1980 have been diagnosed until January 1, 1983. The total frequency of diagnosed cases with sex chromosome abnormalities is 13% of the expected number. Induced abortion was made in 62% of the cases with sex chromosome abnormalities diagnosed prenatally. Ninety percent of all cases with Down's syndrome were diagnosed by chromosome examination, and 10% were diagnosed prenatally and aborted. During the last part of the period from 1977-1980 this had increased to 20%. Thirty-seven percent of cases with other chromosome abnormalities were diagnosed. Among the expected 4,396 children with chromosome abnormalities to be born between 1970 and 1980, a total of 39% were diagnosed postnatally until January 1, 1983, and 10% were diagnosed prenatally. It is concluded that there is a great need for training consultants in clinical genetics, expansion and further decentralization of cytogenetic service with more cytogenetic laboratories and employment of clinical geneticists in all 14 Danish counties.