Molecular techniques focused on detection of common aneuploidies--FISH and QFPCR--provide a quick result in prenatal diagnosis. There is a trend to apply these rapid tests as 'stand-alone' tests which would lead to substantial economical savings. The purpose of the retrospective study is to determine the frequency of chromosomal aberrations (CA) which would be missed by this tool in particular indication groups--residual cytogenetic risk. DESIGN: Retrospective study. SETTING: Department of Medical Genetics and Foetal Medicine University Hospital Olomouc. METHOD: 5305 prenatal samples were examined and the frequency of QFPCR undetected CA (structural and rare aneuploidies) was observed. RESULTS: The residual risk in patients referred for abnormal results of current prenatal screening programs for Down syndrome or for maternal age, without any ultrasound (US) pathological findings, was 0.9%. It was 6.9% in the group where US pathological findings or family history of CA were present. CONCLUSION: The rapid test can replace karyotyping if there is a risk for CA based exclusively on abnormal results of current screening programes for Down syndrome or age related risk, providing that US is normal.

Ústav lékařské genetiky a fetální medicíny FN a LF UP Olomouc

Substitution of prenatal karyotyping with targeted QFPCR - cytogenetic residual risk assessment

Lit.: 18