The underlying genetic cause for your patient’s clinical features can be due to many different types of genetic variations. The genetic variations that FirstStep^Dx PLUS looks for include deletions (missing genetic material) and duplications (extra genetic material) on the chromosomes. The genetic variations that NextStep^Dx PLUS looks for are much smaller and can't be detected by FirstStep^DxPLUS.

One way to look at the difference between how the two tests work is to compare them to a book. FirstStep^Dx PLUS looks for missing or duplicated chapters in a book. NextStep^Dx PLUS looks for misspellings within a single word. Neither test can do the other’s job. If FirstStep^Dx PLUS does not find an underlying genetic cause for your patient's clinical features, performing a NextStep^Dx PLUS test is a way to look at the "book" of your patient's genetic information in a totally different way.

As part of the NextStep^Dx PLUS service, we also offer families the option to opt-in or opt-out of evaluation and interpretation of a secondary gene list. These are genes that may have nothing do with the condition the family was concerned about. They’re genes that might pose an unrelated health risk, like predisposing a member of the family to a hereditary cancer risk or heart condition. Knowing about these genes ahead of time can give people the opportunity to closely monitor their health and take precautions. The American College of Medical Genetics (ACMG) recommended that these genes be included for clinical exome sequencing tests because of their relevance to human disease.

The ACMG recommended secondary gene list can be viewed here.

We estimate the turnaround time to be about 3 to 4 months. Because we are in the early launch phase of offering NextStep^Dx PLUS and because sequencing testing is complex, the turnaround time can fluctuate.