The main clinical manifestations were hypercholesterolemia, premature atherosclerosis, arrhythmia, systemic multiple xanthomas, etc. After genetic testing, it was found that the patients had a compound heterozygous mutation of c.1324+1de1G in exon 7 and exon 9 of chromosome 2p21 of the adenosine triphosphate binding cassette transporter G family member <i>5(ABCG5)</i> gene; the mutation at c.904+1G>A was of maternal origin, and the mutation at c. Here, ABCG5 is linked to cardiac arrhythmia.