title: Down's syndrome in Western Australia: cytogenetics and incidence.
abstract: 235 cases of Down's syndrome were ascertained in a 10-year study of Down's syndrome in Western Australia. Although cytogenetic studies performed on 222 subjects confirmed that 95% of cases were trisomic due to nondisjunction, 4% were trisomic due to translocation, and 1% were mosaic, the ratio of inherited/sporadic translocations differed from that usually reported. Comparison of the results with those of an earlier Australian survey of Down's syndrome demonstrated a real fall in the incidence of Down's syndrome in Australia but no significant change in maternal age-specific incidences.
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia; D002901:Chromosomes, Human, 13-15; D002904:Chromosomes, Human, 21-22 and Y; D004314:Down Syndrome / Q000453:epidemiology* / Q000235:genetics; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D009030:Mosaicism; D014178:Translocation, Genetic; D014314:Trisomy