To test the hypothesis that in patients with a clinical diagnosis of familial hypercholesterolemia (FH), genetic testing and identification of a causative mutation might enhance the success of family-based cascade screening.

To examine the impact of genetic testing on the efficiency of cascade screening for FH, patients with suspected FH or a clinical diagnosis of FH have been randomized to genetic testing or standard of care with lipid testing alone. After systematic encouragement of family enrollment, as a primary endpoint, the compared the number of probands with relatives enrolled in each group one year after results were returned to probands. The secondary endpoints examined include the number of relatives enrolled within 52 weeks of the genetic counseling call and the number of relatives diagnosed with FH through the study. Exploratory subgroup analyses were conducted stratifying the cohort by randomization/genetic test result. Further exploratory analyses compared probands' perceptions about high cholesterol diagnosis at baseline and at 20 weeks from enrollment

Inclusion Criteria:

• For probands, inclusion criteria are as follows:

  1. LDL cholesterol > 220 mg/dL or a previous clinical diagnosis of FH
  2. Aged 18 years or older
  3. Ability to provide informed consent
  4. Willingness/ability to contact a minimum of 2 biological relatives about the study

Exclusion Criteria:

• For family members of probands, inclusion criteria are as follows:

  1. Willingness to participate in the study
  2. Age 10 or older
  3. Ability to give informed consent/assent

IRB approval to share IPD was not obtained for this protocol at the time of the initial protocol submission. If this should be required as part of the peer review process, or after publication of the study results and application will be submitted for a protocol amendment to fulfill this request