1. Testing may not have been performed for the disease you/your child has:
If a panel was performed, variant(s) related to disease may simply be outside of
the area sequenced.
Even if whole exome sequencing (WES) was performed, variant(s) related to
disease may be outside of the exome.
The variant(s) related to disease may be a large copy number variant. Sequencing
assays such as exome have poor sensitivity to detect large gene deletions or
duplications. The appropriate test for detection of these larger variants is a
chromosomal microarray (CMA).
The variant(s) related to disease may be on the mitochondrial DNA (mtDNA),
which is generally NOT included (or well interpreted) if WES is ordered.
The variant(s) related to disease may be a trinucleotide repeat (including fragile X
and many others), which is generally NOT tested for if WES is ordered.
The variant(s) related to disease may be a methylation defect or imprinting error
(including Angelman and many others), which is generally NOT tested for if
WES is ordered.
Upon request and arrangement, our Service can help you or your physician to
understand the meaning and implications of the above testing modalities.
Disease may be non-genetic.
2. Even if all of the above testing was performed, negative test results does not rule out all
genetic causes for disease. It is still possible that your/your child’s symptoms have an
underlying genetic cause or risk factors that the technology used was unable to detect, or
that we do not understand.
3. Some results are of uncertain clinical significance, meaning that while they may be
related to disease, they may also be harmless changes unrelated to disease.
4. Genetics determines risk for disease, but cannot state whether disease will in fact occur,
or the severity of disease, with certainty as knowledge is incomplete and the environment
is also important.
5. This test is not meant to evaluate for carrier status related to reproduction. Most
individuals are apparent carriers for a great number of the genes sequenced by exome,
and with rare exceptions we do not pursue or confirm this data.