• In June, July, and August of 1984, more Infants than usual were born with Down's syndrome in Franklin County, Ohio. A direct physician survey was done, and chromosome reports were reviewed, resulting In the Identification of 11 Infants with Down's syndrome born during that period. Using a ϰ2 analysis, the expected number of affected newborns was five, making the actual number of 11 significant. Although a summertime peak was observed, the yearly incidence of 1.09 per 1000 live births was within the expected range.
Seifert C, Sommer A. A Summertime Peak of Down's Syndrome in Franklin County, Ohio. Am J Dis Child. 1986;140(8):822-824. doi:10.1001/archpedi.1986.02140220104044