What happens after a whole exome sequencing result comes back?

[Anonymous]

What happens after a whole exome sequencing result comes back, and is this testing available in India?

[Genetic Counselor]

A whole exome 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 in the coding regions examined.
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, options often include periodic reanalysis of the existing sequencing data as scientific knowledge improves, since a change unrecognized today is regularly reclassified later; moving on to whole genome sequencing if a broader search seems warranted; or considering chromosomal microarray if it was not already performed, since it can catch certain changes that whole exome sequencing is not designed to see.
• 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 exome sequencing is increasingly available in India through accredited diagnostic and genetics laboratories, and the Indian Academy of Medical Genetics has published specific guidance for its use in Indian clinical practice. This guidance describes whole exome sequencing as a reasonable first-tier test for conditions likely caused by a change within a single gene, while reserving gene panels for situations where the number of genes that could be responsible is more limited, and reserving whole genome sequencing for cases where whole exome sequencing has not provided an answer. 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 a large and complex set of results. Families considering this testing in India are encouraged to confirm that a laboratory holds appropriate accreditation and that genetic counseling, both before and after testing, is included 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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