Genetic testing is recommended for first and second degree relatives of patients with a known FH causing genetic variant. Test orders for cascade testing must include the details of the index patient and the genetic variant found in the family. Where this information is not provided, the sample will be extracted and stored and the East GLH will issue a report indicating the reason for non-acceptance of testing.
How is Cascade Genetic Testing performed for FH?
For cascade testing, the DNA of a family member is tested for the presence or absence of the genetic variant known to cause FH in that particular family. If the FH family variant is not known then cascade testing cannot be performed.
Why is cascade referral at the top of the FH Genetic Testing Pathway and not LDL levels?
First degree relatives are eligible for cascade genetic testing regardless of LDL-Cholesterol levels. Early diagnosis and treatment of FH reduces the risk of cardiovascular events.
What is an index patient?
The term “Index Patient” refers to the first individual within a family where a FH genetic variant was identified.
What is a first degree relative?
First-degree relatives (parents, children, brothers and sisters) of someone with FH should be tested regardless of LDL Cholesterol level.
Should cascade testing be performed in children and young adults?
National guidelines suggest that, where possible, the offspring of anyone with a known FH genetic variant should be tested by the age of 10. If possible it would be helpful to check the child’s lipid profile at the same time as arranging a genetic test. It is worth noting that LDL cholesterol levels decrease during puberty.
Can cascade testing be performed if the FH family genetic variant is not known?
No. Cascade testing cannot be performed if the FH family genetic variant is unknown. If a patient meets the eligibility criteria for diagnostic testing then a diagnostic genetic FH test can be ordered.
Arranging cascade testing for FH
Please use the East Genomics FH test order form to request cascade testing:
