An improved method for the detection of Down's syndrome aneuploidy in uncultured amniocytes.

We report a modified method for the rapid detection of aneuploidies directly on human uncultured amniocytes that simplifies and shortens the entire experimental procedure, yielding signals which allow correct diagnosis of trisomy 21 in 97% of cases. The improvement is based on two points: 1) use of cosmid pockets specific for the Down's syndrome minimal region as FISH probes, and 2) a modified protocol for the fixation and preparation of amniocytes.