What happens after a whole genome sequencing result comes back?

[Anonymous]

What happens after a whole genome sequencing result comes back?

[Genetic Counselor]

A whole genome sequencing result is generally reported in one of three ways: a genetic cause was clearly identified and explains the person’s symptoms; one or more variants of uncertain significance were found, meaning a real change exists but its significance is not yet clear; or no relevant genetic change was identified despite the breadth of the search. What happens next depends on which of these applies:

• When a clear genetic cause is found, a geneticist or genetic counselor explains what the finding means for the person’s health and, where relevant, connects the family with specialists for ongoing management, along with discussing the chance of the condition recurring in future pregnancies or affecting other relatives.
• When a variant of uncertain significance is found, testing close relatives can sometimes help clarify whether the change is likely to be significant, and the finding is generally not used alone to make major medical decisions until more evidence accumulates.
• When no answer is found, the raw sequencing data can often be reanalyzed periodically as scientific knowledge improves, since a change unrecognized today is regularly reclassified later; this is one of the practical advantages of whole genome sequencing, since the original data already covers virtually the whole genetic code and rarely needs to be regenerated from a new sample.
• When secondary findings were requested and identified, families are connected with the relevant specialists for that specific condition, separate from the original reason testing was pursued.

Whole genome sequencing is available in India through a small but growing number of accredited diagnostic and genetics laboratories, though it remains less widely available, and generally costlier with a longer turnaround time, than whole exome sequencing. The Indian Academy of Medical Genetics has published specific guidance for the use of sequencing-based testing in Indian clinical practice, describing whole exome sequencing as a reasonable first-tier test for conditions likely caused by a change within a single gene, while reserving whole genome sequencing for situations where whole exome sequencing has not provided an answer, or where a structural, non-coding, or repeat-expansion cause is specifically suspected. It also stresses that responsible use of this testing depends on early referral to a clinical geneticist, thorough counseling before testing that covers what the test can and cannot answer, and interpretation by laboratories with the training and quality standards needed to correctly classify what is often an especially large and complex set of results. Families considering this testing in India are encouraged to confirm that a laboratory holds appropriate accreditation, that genetic counseling is included both before and after testing as a standard part of the process, and to ask specifically whether testing will be performed as a trio with both parents, since this affects both the speed and the certainty with which results can be interpreted.

[Author]

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