Screening for cytogenetic polymorphisms in a random sample of liveborn infants from Italian population.

: The frequency of major and minor chromosome variants is studied in a random sample of newborns in Central Italy. Special attention is paid to the objective criteria used to evaluate minor variants. In our sample, the frequency of acrocentric chromosome variants is found to be unusually high compared with previous studies. Also, the distribution of C-band sizes differs from that reported for other populations, while the frequency of major chromosome variants is found to be the same.