Objective To screen the point mutation of the low-density lipoprotein receptor (LDL-R) gene in Chinese familial hypercholesterolemia (FH) patients,characterize the relationship between the genotype and the phenotype a...Objective To screen the point mutation of the low-density lipoprotein receptor (LDL-R) gene in Chinese familial hypercholesterolemia (FH) patients,characterize the relationship between the genotype and the phenotype and discuss the molecular pathological mechanism of FH. Methods A patient with clinical phenotype of homozygous FH and her parents were investigated for mutations in the promoter and all eighteen exons of the LDL-R gene. Screening was carried out using Touch-down PCR and direct DNA sequencing; multiple alignment analysis by DNASIS 2.5 was used to find base alteration,and the LDL-R gene mutation database was searched to identify the alteration. In addition,the apolipoprotein B gene (apo B) was screened for known mutations (R3500Q) that cause familial defective apo B 100 (FDB) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).Results Two new heterozygous mutations in exons 4 and 9 of the LDL-R gene were identified in the proband (C122Y and T383I) as well as her parents. Both of the mutations have not been published in the LDL-R gene mutation database. No mutation of apo B 100 (R3500Q) was observed. Conclusion Two new mutations (C112Y and T383I) were found in the LDL-R gene,which may result in FH and may be particularly pathogenetic genotypes in Chinese people.展开更多
Background Familial hypercholesterolemia （FH） is a type of dominant autosomal disease that causes high levels of plasma low-density lipoprotein cholesterol （LDL-C）. In the past years, molecular data related to FH ...Background Familial hypercholesterolemia （FH） is a type of dominant autosomal disease that causes high levels of plasma low-density lipoprotein cholesterol （LDL-C）. In the past years, molecular data related to FH were limited in China. Now, to gain more information about FH, we analyzed one proband with a severe FH phenotype as well as his relatives. Methods After the entire coding sequence and the intron-exon junctions of the low-density lipoprotein receptor （LDLR） gene were amplified using PCR, we sequenced the LDLR gene of a Chinese FH family. RT-PCR was used to detect changes in the mRNA. Results Two novel mutations were identified in the LDLR gene of this family. One, W165X, was a G〉A substitution at the third nucleotide of codon 165. The other, IVS5-1G〉A, was also a G〉A substitution at the acceptor splice site of intron 5. The most striking discovery is that the proband was heterozygous for W165X but homozygous for IVS5-1G〉A. The cDNA sequencing showed that the IVS5-1G〉A mutation caused the insertion of 10 nucleotides, namely GCTCTCACAA, between exon 5 and exon 6. Conclusions The two nucleotide variations are thought to be the FH-causing mutations because the co-segregation of the mutant allele with the phenotype of FH has been shown in this Chinese family. These data show an increase in the mutational spectrum of FH in China and verify a scarce mutational form in the LDLR gene.展开更多
基金ThisstudywassupportedbygrantsfromBeijingNaturalScienceFoundation (No .70 3 2 0 12 )andBase ClinicalMedicineCooperationFoundationofCapitalUniversityofMedicalScience (No .0 2JL19)
文摘Objective To screen the point mutation of the low-density lipoprotein receptor (LDL-R) gene in Chinese familial hypercholesterolemia (FH) patients,characterize the relationship between the genotype and the phenotype and discuss the molecular pathological mechanism of FH. Methods A patient with clinical phenotype of homozygous FH and her parents were investigated for mutations in the promoter and all eighteen exons of the LDL-R gene. Screening was carried out using Touch-down PCR and direct DNA sequencing; multiple alignment analysis by DNASIS 2.5 was used to find base alteration,and the LDL-R gene mutation database was searched to identify the alteration. In addition,the apolipoprotein B gene (apo B) was screened for known mutations (R3500Q) that cause familial defective apo B 100 (FDB) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).Results Two new heterozygous mutations in exons 4 and 9 of the LDL-R gene were identified in the proband (C122Y and T383I) as well as her parents. Both of the mutations have not been published in the LDL-R gene mutation database. No mutation of apo B 100 (R3500Q) was observed. Conclusion Two new mutations (C112Y and T383I) were found in the LDL-R gene,which may result in FH and may be particularly pathogenetic genotypes in Chinese people.
文摘Background Familial hypercholesterolemia （FH） is a type of dominant autosomal disease that causes high levels of plasma low-density lipoprotein cholesterol （LDL-C）. In the past years, molecular data related to FH were limited in China. Now, to gain more information about FH, we analyzed one proband with a severe FH phenotype as well as his relatives. Methods After the entire coding sequence and the intron-exon junctions of the low-density lipoprotein receptor （LDLR） gene were amplified using PCR, we sequenced the LDLR gene of a Chinese FH family. RT-PCR was used to detect changes in the mRNA. Results Two novel mutations were identified in the LDLR gene of this family. One, W165X, was a G〉A substitution at the third nucleotide of codon 165. The other, IVS5-1G〉A, was also a G〉A substitution at the acceptor splice site of intron 5. The most striking discovery is that the proband was heterozygous for W165X but homozygous for IVS5-1G〉A. The cDNA sequencing showed that the IVS5-1G〉A mutation caused the insertion of 10 nucleotides, namely GCTCTCACAA, between exon 5 and exon 6. Conclusions The two nucleotide variations are thought to be the FH-causing mutations because the co-segregation of the mutant allele with the phenotype of FH has been shown in this Chinese family. These data show an increase in the mutational spectrum of FH in China and verify a scarce mutational form in the LDLR gene.
