Do all gene variants affect health and development?
Most gene variants have no impact on health or development, as only a small percentage are responsible for causing genetic disorders.
Overview
Not all gene variants affect health. In many cases, variants alter a gene's DNA sequence without changing the function of the resulting protein. Furthermore, the body possesses various pathways where enzymes recognize and repair DNA errors before a gene is expressed, serving as an important protective mechanism against disease.
In rare instances, a very small percentage of variants have a positive effect. These variants can lead to new versions of proteins that help an individual better adapt to their environment, such as providing protection against a new strain of bacteria.
Classification of Gene Variants
Because many variants have no effect on health, diagnosing genetic disorders can be complex. When evaluating whether a variant is associated with a disorder, scientists analyze how it affects protein function or production and review existing classification data. Variants are categorized into one of five groups:
- Pathogenic: The variant is responsible for causing disease, supported by ample scientific research. These are often referred to as mutations.
- Likely pathogenic: The variant is probably responsible for causing disease, though there is currently insufficient research to be certain.
- Variant of uncertain significance (VUS or VOUS): The role of the variant in disease development cannot be confirmed, either due to conflicting research or a lack of sufficient data.
- Likely benign: The variant is probably not responsible for causing disease, but there is not enough research to be certain.
- Benign: The variant is not responsible for causing disease, with ample scientific research available to disprove an association.
Management and Re-evaluation
Evaluation must be performed for each specific variant, as the presence of a gene associated with a disease does not mean all variants within that gene are pathogenic. Furthermore, a variant that is pathogenic for one disease is not necessarily pathogenic for another.
It is important to re-evaluate variants periodically. As scientific research progresses and more information becomes available, the classification of a variant can change over time.