Reporting of Down's syndrome from birth certificate data in the State of Minnesota.

Following a study of 421 suspected cases of Down's syndrome which were referred during a 10-year period to the Human Genetics Unit of the Minnesota Department of Health for chromosomal analysis, the following conclusions were reached: 1. There was an overall underreporting on the matched birth certificate of 52% of the cytogenetically confirmed cases. 2. This underreporting on birth certificates was greater (79%) for those born in the years 1946-1964 when less specific information was requested than in more recent years (36%), 1967-1974, when identification of the abnormality was requested.