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Familial Hypercholesterolemia (FH) Panel

Test code(s) 94877

Question 1. What is this test used for?

This test is used to detect point mutations, deletions, and duplications in the LDLR, APOB, and PCSK9 genes. Variants in these (and other) genes have been associated with Familial Hypercholesterolemia (FH).

Question 2. Who is this test appropriate for?

This test may be appropriate to confirm a diagnosis of FH for:

  • Individuals with a personal history of hypercholesterolemia or an uncertain clinical diagnosis of FH
    • Clinical diagnostic criteria are available through the Dutch Lipid Clinic Network,1 the Simon Broome Register Group,2 and the US MEDPED Program3
  • Individuals with a personal or family history of developing cardiovascular disease or coronary artery disease at a young age
  • Individuals with a personal or family history of visible lipid deposits in the tendons (tendon xanthoma) or eyes (corneal arcus)

When multiple family members are affected, the person with the earliest symptom onset should be tested first if possible.

Informed consent following genetic counseling is strongly recommended.

Question 3. What test should I order if the patient has an affected family member(s) with a known variant(s)?

If the patient has a known familial variant(s), the Familial Hypercholesterolemia (FH) Single Site test (test code 94878) may be ordered. If you have questions, please call Quest Genomics Client Services at 1.866.GENE.INFO to speak with a genetic counselor.

Question 4. Whom can I ask for help regarding a specific case?

You can ask one of our genetic counselors. Please call Quest Genomics Client Services at 1.866.GENE.INFO to speak with a genetic counselor.

Question 5. When is the right time to test my patient?

Testing is indicated when a diagnosis of FH is suspected or when a clinical diagnosis of FH needs to be confirmed.  You may consider testing patients if they have a personal or family history that meets clinical diagnostics criteria or leads to an uncertain diagnosis.

Question 6. My patient has a positive result. What does this mean?

A patient is considered to have a positive result when at least one pathogenic or likely pathogenic variant has been detected. The presence of a single pathogenic variant is causative of FH. Individuals with FH are at risk of developing high levels of LDL cholesterol (LDL-C), which may increase the risk for premature coronary artery disease and myocardial infarction. Patientswith FH may also develop visible lipid deposits in the tendons (tendon xanthoma) or eyes (corneal arcus). Individuals with FH may have either heterozygous FH (HeFH) or homozygous FH (HoFH). Patients with HoFH tend to have more severe symptoms and/or earlier onset than those with HeFH.

The FH Foundation provides information and resources about FH (https://www.thefhfoundation.org). The National Lipid Association (https://www.lipid.org) and the European Atherosclerosis Society (https://www.eas-society.org) also provide management guidelines. Consider referring the patient to a center experienced in treating patients with FH. Counselors at these centers can discuss treatment options with the patient. Genetic counseling for family members is advised.

Question 7. My patient has a negative result. What does this mean?

A negative result means that a pathogenic or likely pathogenic variant was not found in the LDLR, APOB, or PCSK9 genes. Implications of this result depend on the patient’s personal medical history and family history:

  • Patient with elevated LDL-C levels: Your patient should continue to be managed based on current guidelines. A negative result does not eliminate the possibility of FH, as other known or unknown genes may cause this phenotype. In some situations, additional genetic testing may be appropriate. Please call Quest Genomics Client Services at 1.866.GENE.INFO to discuss possible additional testing with a genetic counselor.
  • Patient without elevated LDL-C levels, with family history suspicious for FH: Testing an affected family member is recommended for proper risk assessment. In some situations, additional genetic testing may be appropriate. Please call Quest Genomics Client Services at 1.866.GENE.INFO to discuss possible additional testing with a genetic counselor.

Question 8. My patient has a variant of unknown clinical significance (VUS). What does this mean?

A VUS result means that the variant has not been previously described in the literature or the clinical significance is unclear based upon currently available evidence. Medical management decisions should be based on personal and family history. If you have questions, please call Quest Genomics Client Services at 1.866.GENE.INFO to speak with a genetic counselor.

References

  1. World Health Organization (WHO). Familial hypercholesterolaemia (FH): report of a second WHO Consultation, Geneva, 4 September 1998. Geneva, Switzerland: World Health Organization; 1991.
  2. Simon Broome Register Group. Risk of fatal coronary heart disease in familial hypercholesterolemia. BMJ. 1991;303:893-896.
  3. Williams RR, Hunt SC, Schumacher C, et al. Diagnosing heterozygous familial hypercholesterolemia using new practical criteria validated by molecular genetics. Am J Cardio. 1993;72(2):171-176.
This FAQ is provided for informational purposes only and is not intended as medical advice. A clinician’s test selection and interpretation, diagnosis, and patient management decisions should be based on his/her education, clinical expertise, and assessment of the patient.
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Effective 3/19/2018 to present