Further testing

Depending on the result of genomic testing, further testing may be required/offered.

If uncertain results are obtained, further testing may help to clarify the significance of a variant (e.g., classify as pathogenic or benign). Segregation testing and functional studies may assist here.

• Segregation testing – often used to determine the inheritance pattern of a variant (e.g., dominant, recessive or de novo), or to help establish pathogenicity of an uncertain variant. It’s performed by testing the parents of the proband (patient), or other affected family members.
• Functional studies – a way of testing the impact of a particular variant by comparing against a normal. For example, using cell lines or animal studies, you can determine the effect of the variant on the resulting protein and therefore, the clinical impact.

If a pathogenic variant is identified in a patient, this information could be useful for other family members, especially to prevent onset or reduce severity of the disease by a lifestyle or medical intervention. In this case, cascade testing is offered.

• Cascade testing – testing of biological relatives in order to prevent onset or modify severity of disease.