NextStepDx PLUS®

Patients who have had genetic tests, particularly a chromosomal microarray test like the FirstStepDx PLUS®, but did not find a genetic cause underlying their condition, are candidates for NextStepDx PLUS® genetic sequencing test.

NextStepDx PLUS is a whole exome sequencing test designed to identify genetic variants that are associated with disorders of childhood development. NextStepDx PLUS is another way of looking at the genome and may provide the diagnosis parents are looking for.

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

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

As part of the NextStepDx 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.

For patients who have had a FirstStepDx PLUS test, we use buccal swab sample similar to FirstStepDx PLUS. In the event that we need an additional buccal swab from the patient, or if the family chooses to include parent DNA as part of the testing process, Lineagen personnel will coordinate additional sample collection. A buccal swab kit will be sent to the family directly or to the provider’s office. Lineagen covers the cost of shipping.

As NextStepDx PLUS is a clinical product performed in a CLIA-certified laboratory and requested by the patient’s provider, Lineagen will bill the patient’s insurance company. Pre-test and post test genetic counseling sessions are available as part of our NextStepDx PLUS genetic testing service.

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

NextStepDx PLUS should be ordered by a doctor or other healthcare provider (physician assistant, nurse practitioner). If you are interested in NextStepDx PLUS for your child, please contact your child’s healthcare provider to discuss genetic testing. Lineagen’s licensed and certified genetic counselors are also available at 801-931-6191 to answer questions about NextStepDx PLUS.

A genetic test can pinpoint the genetic cause of your child’s delays, help identify the most effective treatment and give you and your family a more clear understanding about what to expect regarding your child’s development.
Rena Vanzo
MS, LCGC Licensed & Certified Genetic Counselor,
Vice President, Clinical Services, Lineagen, Inc.