Chromosomal anomalies in 1,000 children referred with suspected genetic disorders.

One thousand children ranging from newborns to 13 years of age with a variety of clinical disorders were referred to us to investigate the possible presence of chromosomal abnormalities. Various types of chromosomal anomalies were found in 166 children (16.6%), which is significantly (p < 0.01) higher than in an unselected (control) population (0.48-0.55%). The male:female ratio was 3:2 for the total population. Furthermore, in our survey population, the sex ratio of Down's syndrome cases of males to females was 3:2.