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Seven-point genetic testing may identify more patients with FH
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MIAMI — Adding four more genes to traditional genetic testing may identify more patients with familial hypercholesterolemia, which may be especially beneficial for black patients in whom traditional scoring criteria may not be sufficient, according to data from the second-place oral poster winner presented at the National Lipid Association Scientific Sessions.
Genetic testing
Allison Hester, PharmD, second-year ambulatory care pharmacy resident at Grady Health Services in Atlanta; Terry Jacobson, MD, FNLA, professor of medicine at Emory University, director of the Office of Health Promotion and Disease Prevention and co-director of the lipid and CV risk reduction program at Grady Health Systems; Mary Katherine Cheeley, PharmD, CLS, FNLA, clinical pharmacist in primary care at Grady Health Systems, and colleagues analyzed genetic data from 100 patients (median age, 58 years; 27% women; 97% self-identified black) with an LDL of at least 190 mg/dL from the Grady Health System, which is an urban safety-net hospital with an advanced lipid clinic.
There are two ways to reach a FH diagnosis, one of them being clinical scoring systems such as the Dutch Lipid Criteria and Simon Broome Diagnostic Criteria, both of which take into account family history, clinical history, physical examination and cholesterol level. The other is genetic testing, which, while often expensive, only tests for LDL-R, Apolipoprotein B and PCSK9 and is not 100% sensitive for the genes it tests, according to the presentation.
Both methods have issues especially in the patient population seen in this study, as clinical scoring criteria were developed from predominately white populations and do not particularly focus on underserved patient populations, Hester said.
“A lot of [these patients] have significant social barriers including the fact that many do not have their family history,” Hester said during the presentation. “Some of their parents may have passed away at a young age from a nonmedical cause or some of them did not grow up with their biological parents, so we have a really hard time getting anyone to accumulate the needed points on any clinical scoring criteria.”
There are also barriers for genetic testing in these patients such as affordability, insurance companies not covering the testing and the fact that many underserved patients do not trust the medical system and providers, according to the presentation.
Study design
For this study, a seven-gene genetic test was performed and included LDL-R, Apo B, PCSK9, Apolipoprotein E, LDLRAP1, cholesterol ester transfer protein and sterol regulatory element binding transcription factor 1.
Of the patients in the study, 12 had positive genetic tests, eight of whom had a positive LDL receptor test, three of whom tested positive for Apolipoprotein E and one of whom tested positive for Apolipoprotein B.
“This is probably different than we would have expected,” Hester said during the presentation.
When comparing patients who tested positive with those who tested negative, characteristics that did not have statistically significant differences include family history of atherosclerotic CVD, Dutch Lipid Score and lipoprotein(a). In contrast, patients who tested positive were younger (46 years vs. 58 years; P = .004) and had higher LDL (272 mg/dL vs. 227 mg/dL; P < .001) compared with patients who tested negative.
“More studies are needed to determine which genes are optimal to screen for genetic hypercholesterolemia in minority populations,” Hester said during the presentation. – by Darlene Dobkowski
Reference:
Hester A. Session VII: Clinical Pearls. Presented at: National Lipid Association Scientific Sessions; May 16-19, 2019; Miami.
Disclosures: The study was funded by an investigator-initiated grant from Sanofi/Regeneron. The genetic tests performed in the study were donated by MyGenetx Laboratory. Hester reports no relevant financial disclosures. Cheeley reports she consults for Regeneron Pharmaceuticals. Jacobson reports he is a consultant for Amarin, Amgen, Regeneron and Sanofi.