The study gives updated results of incidences analysis of both pre- and postnatally diagnosed chromosomal birth defects in the Czech Republic during the 1994-2007 period. Incidences found in our study correspond (in case of trisomies 13, 18 and 21) with those published widely in literature as well as with those found in large-scale international studies (ICBDSR, EUROCAT).
In case of gonosomal aberrations, incidences found in this study are lower that those published, most probably due to a later registration (over 15 years of age of the child) of these diagnoses.