Institut de Puericulture et de Perinatologie, Paris, France.

This is a case of trisomy 21 and a few pictures showing hierarchy of the diagnostic process leading from ultrasonographic investigation to definitive chromosomal diagnosis.

Images 1, 2. Abnormal nuchal translucency.

Images 3, 4. Abnormal nuchal translucency (3); and tricuspid regurgitation (4).

Image 5. Abnormal ductus venosus waveform pattern.

Images 6, 7. Ultrasound targeted chorionic villi sampling.

Images 8, 9. The obtaining and processing of biological material (chorionic villi).

Images 10, 11. Sample of chorionic villi and definitive chromosomal diagram showing redundant chromosome 21.