Compound Heterozygosis Mutation of Low Density Lipoprotein Receptor Gene in Familial Hypercholestero-lemia Family / 实用儿科临床杂志

ABSTRACT

Objective To identify mutations site and clinical characteristics of a familial hypercholesterolemia(FH) proband diagnosed clinically through DNA sequencing and family analysis in the proband and his family members of 3 generations.Methods Blood samples and clinical data of the kindred of total 29 from 3 generations members were collected.Proband had a physical examination electrocar-diogrom and vascular ultrasound.The proband and his family members took routine clinical exams,and genomic DNA was isolated.The promoter region and the 18 exons of low density liporotein receptor(LDLR) gene were screened by Touch down polymerase chain reaction -single strand conformation polymorphism(PCR-SSCP) and DNA sequencing.The result of sequencing were matched gene sequence published in the BLAST database.Results 1.Increased intima-media thickness and plaque were detected in the common carotid artery,right subclavian artery of the proband.Aortic valve regurgitation was found by echocardiography.2.No mutation R3500Q of ApoB100 was observed.3.Two heterozygous mutations in exon 10 and 13 of LDLR gene (W462X and A606T) were identified.The proband and 5 members of paternal relatives showed W462X heterozygosis mutation in exon 10 of LDLR gene which introduced the change from tryptophone to a new stop codon.The proband's mother and grandmother harboured A606T heterozygous mutation in exon 13 of LDLR gene due to a single base pair substitution of G for A in the codon for residue 1 879.Conclusions Disease causing mutations of proband are W462X and A606T compound heterozygosis mutation in exon 10 and 13 of LDLR gene inherited from mother and father.Proband shows homozyous phenotype though the genotype analysis indicates heterozygous mutations.