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Abstract：
BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder. The primary objective of this study was to identify the major pathogenic mutations in a Chinese family with FH.
METHODS: Whole-genome sequencing (WGS) was used to identify variants of FH-related genes, including low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin 9 (PCSK9). Bioinformatics software was used to predict signal peptides, transmembrane structures, and spatial construction information of the mutated sequences. Western blotting was performed on the mutant protein to determine the presence of the major structural domains of the LDLR. The PCSK9 and APOB genes were screened and analyzed. Moreover, the proband and his brother were treated with a PCSK9 inhibitor for 1 year, and the effect of the treatment on lipid levels was assessed.
RESULTS: WGS revealed two potentially pathogenic mutations in the LDLR gene. One was a novel mutation, c.497delinsGGATCCCCCAGCTGCATCCCCCAG (p. Ala166fs), and the other was a known pathogenic mutation, c.2054C>T (p. Pro685Leu). Bioinformatics prediction and in vitro experiments revealed that the novel mutation could not be expressed on the cell membrane. Numerous gene variants were identified in the APOB gene that may have a significant impact on the family members with FH. Thus, it is suggested that the severe manifestation of FH in the proband primarily resulted from the cumulative genetic effects of variants in both LDLR and APOB. However, a subsequent study indicated that treatment with a PCSK9 inhibitor (Evolocumab) did not significantly reduce the blood lipid levels in the proband or his brother.
CONCLUSIONS: The cumulative effect of LDLR and APOB variants was the primary cause of elevated blood lipid levels in this family. However, PCSK9 inhibitor therapy did not appear to be beneficial for the proband. This study emphasizes the importance of genetic testing in determining the most suitable treatment options for patients with FH.
METHODS: Whole-genome sequencing (WGS) was used to identify variants of FH-related genes, including low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin 9 (PCSK9). Bioinformatics software was used to predict signal peptides, transmembrane structures, and spatial construction information of the mutated sequences. Western blotting was performed on the mutant protein to determine the presence of the major structural domains of the LDLR. The PCSK9 and APOB genes were screened and analyzed. Moreover, the proband and his brother were treated with a PCSK9 inhibitor for 1 year, and the effect of the treatment on lipid levels was assessed.
RESULTS: WGS revealed two potentially pathogenic mutations in the LDLR gene. One was a novel mutation, c.497delinsGGATCCCCCAGCTGCATCCCCCAG (p. Ala166fs), and the other was a known pathogenic mutation, c.2054C>T (p. Pro685Leu). Bioinformatics prediction and in vitro experiments revealed that the novel mutation could not be expressed on the cell membrane. Numerous gene variants were identified in the APOB gene that may have a significant impact on the family members with FH. Thus, it is suggested that the severe manifestation of FH in the proband primarily resulted from the cumulative genetic effects of variants in both LDLR and APOB. However, a subsequent study indicated that treatment with a PCSK9 inhibitor (Evolocumab) did not significantly reduce the blood lipid levels in the proband or his brother.
CONCLUSIONS: The cumulative effect of LDLR and APOB variants was the primary cause of elevated blood lipid levels in this family. However, PCSK9 inhibitor therapy did not appear to be beneficial for the proband. This study emphasizes the importance of genetic testing in determining the most suitable treatment options for patients with FH.
摘要：
背景：家族性高胆固醇血症（FH）是一种常染色体显性遗传障碍。这项研究的主要目的是确定中国FH家族中的主要致病突变。
方法：全基因组测序（WGS）用于鉴定FH相关基因的变体，包括低密度脂蛋白受体（LDLR），载脂蛋白B（APOB），和前蛋白转化酶枯草杆菌蛋白酶/kexin9（PCSK9）。生物信息学软件用于预测信号肽，跨膜结构，和突变序列的空间构造信息。对突变蛋白进行蛋白质印迹以确定LDLR的主要结构域的存在。筛选并分析PCSK9和APOB基因。此外，先证者和他的兄弟用PCSK9抑制剂治疗了1年，并评估治疗对血脂水平的影响。
结果：WGS揭示了LDLR基因中的两个潜在致病性突变。一个是新的突变，c.497delinsGGATCCCCCCCAGCTGCATCCCCCAG（第Ala166fs)，另一种是已知的致病突变，c.2054C>T（p。Pro685Leu)。生物信息学预测和体外实验表明，新的突变不能在细胞膜上表达。在APOB基因中鉴定出许多可能对FH家族成员具有显著影响的基因变体。因此，提示先证者中FH的严重表现主要是由于LDLR和APOB变异的累积遗传效应。然而,随后的一项研究表明,PCSK9抑制剂(Evolocumab)治疗未显著降低先证者或其兄弟的血脂水平.
结论：LDLR和APOB变异体的累积效应是该家族血脂水平升高的主要原因。然而,PCSK9抑制剂疗法似乎对先证者没有益处。这项研究强调了基因检测在确定FH患者最合适的治疗方案中的重要性。
方法：全基因组测序（WGS）用于鉴定FH相关基因的变体，包括低密度脂蛋白受体（LDLR），载脂蛋白B（APOB），和前蛋白转化酶枯草杆菌蛋白酶/kexin9（PCSK9）。生物信息学软件用于预测信号肽，跨膜结构，和突变序列的空间构造信息。对突变蛋白进行蛋白质印迹以确定LDLR的主要结构域的存在。筛选并分析PCSK9和APOB基因。此外，先证者和他的兄弟用PCSK9抑制剂治疗了1年，并评估治疗对血脂水平的影响。
结果：WGS揭示了LDLR基因中的两个潜在致病性突变。一个是新的突变，c.497delinsGGATCCCCCCCAGCTGCATCCCCCAG（第Ala166fs)，另一种是已知的致病突变，c.2054C>T（p。Pro685Leu)。生物信息学预测和体外实验表明，新的突变不能在细胞膜上表达。在APOB基因中鉴定出许多可能对FH家族成员具有显著影响的基因变体。因此，提示先证者中FH的严重表现主要是由于LDLR和APOB变异的累积遗传效应。然而,随后的一项研究表明,PCSK9抑制剂(Evolocumab)治疗未显著降低先证者或其兄弟的血脂水平.
结论：LDLR和APOB变异体的累积效应是该家族血脂水平升高的主要原因。然而,PCSK9抑制剂疗法似乎对先证者没有益处。这项研究强调了基因检测在确定FH患者最合适的治疗方案中的重要性。
