Failure of lipid control by PCSK9 inhibitors in compound heterozygous familial hypercholesterolemia complicated with premature myocardial infarction: A case report.

KEY CLINICAL MESSAGE

A certain level of low-density lipoprotein receptor activity is crucial for the efficacy of PCSK9i. Therapeutic strategies for familial hypercholesterolemia patients should consider drug efficacy, and genetic testing will be helpful.

ABSTRACT

Familial hypercholesterolemia (FH) is a serious autosomal dominant disorder. Managing blood lipids in FH patients poses greater challenges for clinicians. Drug therapy may not always yield satisfactory results, particularly in individuals with low-density lipoprotein receptor (LDLR) negative mutations. Herein, we report a young female harboring an LDLR frameshift mutation. This patient developed xanthomas at 7 months old and underwent several years of treatment involving four classes of lipid-lowering drugs, including PCSK9i. However, the response to drug therapy was limited in this patient and eventually culminated in premature myocardial infarction. The efficacy of PCSK9i depends on the activity of LDLR. The inefficacy of PCSK9i may arise from the extensive mutations which leading to loss of LDLR activity. Therapy plans for these patients should take into account the efficacy of drug therapy. Early genetic testing is crucial for clinicians to make informed decisions regarding therapy options.