[Analysis on gene mutations in a Chinese pedigree with autosomal dominant inheritance cataract].

OBJECTIVE: The aim of this study was to reveal the genetic defect of the autosomal dominant inheritance cataract in a Chinese pedigree. METHODS: Case-control study. There were 26 individuals investigated with clinical examination in a Chinese four generations pedigree. The genome DNA of the individuals was extracted by the improved NaI method. The exons of six cataract candidate genes in 204 normal controls and 42 senile cataract patients were screened for the mutation by PCR restriction fragment length polymorphism (PCR-RFLP) methods. RESULTS: The phenotype of the cataract was pulverulent nuclear cataract. A novel C/T transition at nucleotide position 827 was identified in the GJA8 gene that led to a serine to phenylalanine change in codon 276. This mutation was not found in 42 senile cataract patients and in 204 controls. Four single nucleotide polymorphisms (SNPs) were also found in a cataract candidate gene in the family members. CONCLUSIONS: A novel GJA8 gene mutation was found in a Chinese autosomal dominant inheritance cataract pedigree. A substitution, C276T in GJA8 gene, was identified as the most likely causative mutation underlying the phenotype of pulverulent nuclear cataract in all affected family members.

[Mutation screening and functional analysis of low density lipoprotein receptor in a familial hypercholesterolemia family].

OBJECTIVE: To screen the mutations of the low density lipoprotein receptor (LDLR) gene in a familial hypercholesterolemia (FH) family, and analyze the LDL-uptaking function of LDLR on lymphocytes of patients. METHODS: Genomic DNA was extracted from four affected members in a Chinese FH family. The presence of apoB100 gene R3500Q mutation which results in familial defective apolipoprotein B100 (FDB) was excluded first. Fragments of the LDLR gene were amplified by touch-down polymerase chain reaction (Touch-down PCR) and analyzed by single-strand conformational polymorphism (SSCP). The suspect fragments of the LDLR gene were cloned and sequenced. Furthermore, the lymphocytes bounded with fluorescent-labeled LDL (DiI-LDL) were measured by fluorescence flow cytometry. RESULTS: A nonsense mutation was identified in exon 10 of LDLR gene. This mutation gave rise to a premature stop codon (W462X), resulting in the absence of most of the LDLR domains. It was detected in all the affected members of the FH family. The ratios of functional LDLR in lymphocytes from patients and normal controls were 63.7% and 77.3% respectively. As a result, the activity of the functional LDLR in patients was just 82.4% of that in the normal controls. CONCLUSION: It is possible that the W462X mutation of LDLR gene is the main cause for the disease in this family.

Polymorphism in ERCC1 confers susceptibility of coronary artery disease and severity of coronary artery atherosclerosis in a Chinese Han population.

Excision repair cross-complementing 1 (ERCC1) gene encodes ERCC1 protein, which is mainly responsible for the repair of DNA damage in different diseases including coronary artery atherosclerosis by acting as a rate-limiting element in nucleotide excision repair (NER). Using a three-stage case-control study with 3037 coronary artery disease (CAD) patients and 3002 controls, we investigated associations of three single nucleotide polymorphisms (SNPs) with CAD risk and severity of coronary artery atherosclerosis in Chinese Han population. In the discovery set, the variant allele T of rs11615 was significantly associated with higher CAD risk (adjusted OR = 1.27, P = 0.006) and severity of coronary artery atherosclerosis (adjusted OR = 1.54, P = 0.003). These associations were more remarkable in the merged set (adjusted OR = 1.23, P = 8 × 10-6 for CAD risk; adjusted OR = 1.36, P = 4.3 × 10-5 for severity of coronary artery atherosclerosis). And the expression level of ERCC1 was significantly higher in CAD cases than controls. Multiplicative interactions among SNP rs11615, alcohol drinking, history of T2DM, and history of hyperlipidemia could increase 5.06-fold risk of CAD (P = 1.59 × 10-9). No significant association of rs2298881 and rs3212986 with CAD risk was identified. Taken together, SNP rs11615 in ERCC1 gene might confer susceptibility to CAD and severity of coronary atherosclerosis in a Chinese Han population.

miR-22 targets YWHAZ to inhibit metastasis of hepatocellular carcinoma and its down-regulation predicts a poor survival.

Many miRNAs are associated with the carcinogenesis of hepatocellular carcinoma (HCC) and some exhibit potential prognostic value. In this study, to further confirm the prognostic value of miRNAs in HCC, we employed miRNA-sequencing data of tumor tissues of 372 HCC patients released by The Cancer Genome Atlas (TCGA) and identified 3 miRNAs including miR-22, miR-9-1 and miR-9-2 could be used as independent predictors for HCC prognostic evaluation. As a tumor-suppressive miRNA, miR-22 was down-regulated in HCC tissues. This down-regulation correlated with tumor vascular invasion, Edmondson-Steiner grade, TNM stage, and AFP level. Moreover, biofunctional investigations revealed that miR-22 significantly attenuated cellular proliferation, migration and invasion of HCC cells. Additionally, through gene expression profiles and bioinformatics analysis, YWHAZ was identified to be a direct target of miR-22 and its overexpression partially counteracted the inhibitory effects of miR-22 on HCC cells. Finally, molecular studies further confirmed that miR-22 promoted the accumulation of FOXO3a in nucleus and subsequently reversed invasive phenotype of HCC cells by repressing YWHAZ-mediated AKT phosphorylation. Taken together, these data demonstrate that miR-22 exhibits tumor-suppressive effects in HCC cells by regulating YWHAZ/AKT/FOXO3a signaling and might be used as an independent prognostic indicator for HCC patients.