[Cytogenetic studies in clinical diagnosis --analysis of 1611 examination results]

An analysis of the frequency and type of chromosome aberrations found in 1611 cytogenetic studies has been done in relation to the clinical indications. The most frequent reason for referral was: MCM/MR syndrome (15.4% cases), suspicion of sex chromosome abnormality (13.1%), Down syndrome (11.2%) and reproductive wastage (10.6%). The incidence of abnormal karyotypes in these groups of patients was 10.1%, 24.2%, 87.9% and 9.3% per couple, respectively. The lowest percentage of chromosome aberrations was found among patients with nonspecific mental retardation (2.2%) and in the families who lost a baby with MCM Syndrome (3.3% per couple). On the whole, abnormal karyotype was found in 364 patients (22.6%). Among 62 families identified by the affected child with, structural chromosome aberration in 24 families (38.7%) the abnormality was familial in the origin.