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

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder, and a genetic analysis is important to make a definitive diagnosis. A comprehensive genetic analysis using next generation sequencing (NGS) and whole exome sequencing (WES) is feasible. However, the application of NGS in the assessment of genomic structural variations is generally limited, and a substantial number of control samples are needed for such assessments. Thus, NGS alone is unlikely to detect genomic structural variations in a “singleton.” We present the case of a patient with compound HeFH (heterozygous FH), whose causative mutations in the LDLR gene could not be identified by WES, necessitating the application of the multiplex ligation-dependent probe amplification (MLPA) technique.