Whole Exome Sequencing Insufficient for a Definitive Diagnosis of a Patient with Compound Heterozygous Familial Hypercholesterolemia

Clinical Characteristics of Homozygous Familial Hypercholesterolemia in Japan: A Survey Using a National Database

Background

The studies evaluating patients' characteristics and lipid-lowering therapy for patients with homozygous familial hypercholesterolemia (HoFH) are scarce.

Objectives

This study aims to evaluate the characteristics of and treatments for patients with HoFH.

Methods

This study included 201 patients who were diagnosed with definite or probable HoFH from the National Database of the Japanese Ministry of Health, Labour, and Welfare.

Results

The patients' median age at diagnosis was 27 years and exhibited a bimodal distribution. Approximately 70% of patients had coronary artery disease. Regarding genetic backgrounds, mutations in the low-density lipoprotein (LDL) receptor (LDLR) were identified in most of the patients, followed by proprotein convertase subtilisin/kexin type 9 (PCSK9) and double heterozygotes of LDLR. High-intensity statins were introduced to 74% of the patients, lipoprotein apheresis was performed in 21%, and PCSK9 inhibitors were administered to 50%. The mean of LDL cholesterol before and after treatment were 10.1 mmol/L and 3.9 mmol/L, respectively. Patients with coronary artery disease had significantly decreased LDL cholesterol. A quarter of the patients (n = 49, 24%) exhibited valvular diseases, particularly aortic valvular disease (n = 34, 61%).

Conclusions

The national epidemiological study of patients with HoFH showed patient's clinical and genetic characteristics and LDL-lowering therapy in Japan. There was considerable diversity in the severity of phenotypes, including LDL cholesterol levels, among patients with HoFH. In Japan, the management of LDL cholesterol in HoFH is still inadequate despite the availability of intensive lipid-lowering therapies.