A woman has an amniocentesis at 17 weeks after a cell-free DNA test reported a high chance of trisomy 21. She…

Question

A woman has an amniocentesis at 17 weeks after a cell-free DNA test reported a high chance of trisomy 21. She is booked to fly interstate in three days for a family funeral and is extremely anxious. She asks whether anything at all can be known before she leaves. The sample is adequate and uncontaminated. Which one of the following tests on the amniotic fluid will give her a reliable answer about trisomy 21 most quickly?

Accepted Answer

Fluorescence in situ hybridisation.

Answer

Chromosomal microarray.

Answer

Karyotype on cultured amniocytes.

Answer

Methylation studies for chromosome 15.

Answer

Whole exome sequencing.

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