All individuals’ specimens should be submitted at the beginning of testing. Relative specimens may be collected and shipped separately from the patient specimen; however, relative specimens must be received within three weeks of receipt of the patient’s specimen. In general, only a single report will be issued for in the patient’s name only. However, the report will describe the inheritance and segregation of variants for all tested individuals.
When a trio (patient plus both parents) is sent for XomeDx®, XomeDx®Plus, or GenomeSeqDx, sequencing is always performed on each member of the trio. This improves the sensitivity of the analysis when compared to testing only the patient.
In some cases, including siblings or other relatives of the patient can be helpful. GeneDx will decide, in consultation with the ordering provider, which individuals will optimize our ability to identify a genetic cause of the patient’s features. We will also discuss the type of testing that is most useful and appropriate (i.e. exome sequencing or targeted variant testing to determine segregation).
Although sequence data may be generated on relatives, this data is only used to aid in the analysis of the patient’s data. GeneDx does not conduct an independent analysis on relative specimens. A second, independent analysis on a relative can be ordered; additional fees apply.
Can I send a different relative if a parent is unavailable for XomeDx®, XomeDx®Plus, or GenomeSeqDx testing?
Biological parents are typically the most informative specimens and are preferred whenever possible. If parents are unavailable, other relatives may be considered on a case-by-case basis. To review details of a specific case, you can contact a GeneDx Clinical Genomics Genetic Counselor at firstname.lastname@example.org or 1-888-729-1206.
Is sequencing via a trio better than a patient alone?
The diagnostic rate is highest when a trio is submitted/analyzed, as the inclusion of parental data improves the ability to classify variants. The absence of parental data may lead to the over reporting of variants of unknown significance that could otherwise be dismissed based on inheritance patterns.