Prenatal diagnosis of genomic disorders and chromosome abnormalities using array-based comparative genomic hybridization

Cytogenetic analysis is a crucial tool of prenatal diagnosis. The ability to rapidly detect aneuploidy and identify small structural abnormalities of foetal chromosomes has been greatly improved by the use of molecular cytogenetic technologies. Microarray-based Comparative Genomic Hybridization (aCGH) has been recently employed in postnatal diagnosis of cryptic chromosomal aberrations, but use in prenatal diagnosis is still limited.We set-up a diagnostic protocol which uses aCGH technology on genomic DNA isolated from uncultured chorionic villus sampled at 11-12 week's gestation. We used a commercially targeted microarray (MDTelArray, Technogenetics Srl - Bouty Group, Sesto S. Giovanni, Milan, Italy) constituted by 167 genomic clones corresponding to 34 critical regions frequently involved in microdeletions and microduplications and 126 subtelomeric clones. Array validation has been carried-out via retrospective analysis of DNA isolated from a series of cytogenetically normal chorionic villus samples (CVS) and of DNA isolated from cytogenetically abnormal cultured amniocytes, CVS or peripheral blood. A pilot prospective study was undertaken analyzing 25 CVS obtained from foetuses at risk for chromosomal aberrations. aCGH results both for retrospective and prospective studies were in agreement with data obtained using "classical" cytogenetic analysis, and/or FISH analysis or DNA testing. Although these preliminary data support the usefulness of aCGH in prenatal diagnosis, further prospective studies are required to verify the feasibility of introducing this technique as part of the diagnostic armamentarium for identify affected foetuses.