PCSK9 and xanthoma: The homozygous nucleotide variants (c.514G > C [p.Asp172His]), harbored in exon 4 of the LDLR gene, and c.158C > T [p.Ala53Val], located in exon 1 of the PCSK9 gene) were identified in an 11-year-old girl, who had undergone heart valve replacement and had high levels of TC (417 mg/dL), LDL-C (240 mg/dL), and xanthomas, with the latter seen in her knees and elbows and between her fingers.