👤 Yongjie Xin

To investigate the association between two polymorphisms of the APOC3 gene (T-455C and C-482T) and hereditary risk of non-alcoholic fatty liver disease (NAFLD). A total of 287 patients with NAFLD and 310 control subjects were genotyped by PCR and direct sequencing. Serum lipid profiles were also detected by standard biochemical One-hundred-and-eighty of the study participants were used to measure the APOC3 content by enzyme-linked immunosorbent assay. Inter-group differences and associations were assessed statistically using Chi square and t tests and logistic and linear regression analyses. The frequencies of neither the genotypes or alleles were significantly different between the NAFLD cases and the controls. Compared with the most common genotypes-455TT or-482CC, none of the variants showed a significant increase in risk of NAFLD or for the clinical and biochemical parameters. The adjusted odds ratios (with 95% confidence intervals) of NAFLD were 1.25 (0.79-1.96) and 1.20 (0.76-1.89) for carriers of the APOC3-455C and-482 T variants respectively (P more than 0.05). The T-455C and C-482T polymorphisms of the APOC3 gene are not associated with risk of NAFLD, pathogenic changes in lipid profiles, or insulin resistance in Han Chinese. Show less

To investigate the association between two polymorphisms of apolipoprotein C3 (APOC3) and risk of nonalcoholic fatty liver disease (NAFLD) in a Chinese Han population. Genotypes for rs2854116 and rs2854117 in APOC3 and the known rs738409 in patatin-like phospholipase domain-containing protein 3 (PNPLA3) in 390 patients with NAFLD and 409 control subjects were determined by sequencing and polymerase chain reaction analysis. Serum lipid profiles were determined using biochemical methods, and an index of insulin resistance (IR, HOMA-IR), serum APOC3 concentrations and total antioxidant status (TAS) were also assessed. No significant differences in genotype and allele frequencies of rs2854116 and rs2854117 were found between the NAFLD population and the controls (P > 0.05). The OR for the association between -455C and -482T allele carriers and the risk of NAFLD were 1.06 (95%CI: 0.72-1.57, P > 0.05) and 1.00 (95%CI: 0.68-1.48, P > 0.05), respectively. The variant carriers did not have a significantly increased risk of NAFLD or elevated clinical and biochemical parameters such as APOC3 concentrations, IR (1.42 ± 0.43 vs 1.48 ± 0.52, P > 0.05), liver enzymes and TAS (13.94 ± 2.01 vs 14.38 ± 1.92, P > 0.05) compared with the controls. Moreover, the results were similar when testing was carried out independent of the genetic variation in PNPLA3. The two polymorphisms of the APOC3 gene are not associated with a risk of NAFLD, or with lipid profiles, IR and oxidative stress in the Chinese Han population. Show less

The Hairy-related transcription factor family of Notch- and ALK1-downstream transcriptional repressors, called Hrt/Hey/Hesr/Chf/Herp/Gridlock, has complementary and indispensable functions for vascular development. While mouse embryos null for either Hrt1/Hey1 or Hrt2/Hey2 did not show early vascular phenotypes, Hrt1/Hey1; Hrt2/Hey2 double null mice (H1(ko) /H2(ko) ) showed embryonic lethality with severe impairment of vascular morphogenesis. It remained unclear, however, whether Hrt/Hey functions are required in endothelial cells or vascular smooth muscle cells. In this study, we demonstrate that mice with endothelial-specific deletion of Hrt2/Hey2 combined with global Hrt1/Hey1 deletion (H1(ko) /H2(eko) ) show abnormal vascular morphogenesis and embryonic lethality. Their defects were characterized by the failure of vascular network formation in the yolk sac, abnormalities of embryonic vascular structures and impaired smooth muscle cell recruitment, and were virtually identical to the H1(ko) /H2(ko) phenotypes. Among signaling molecules implicated in vascular development, Robo4 expression was significantly increased and activation of Src family kinases was suppressed in endothelial cells of H1(ko) /H2(eko) embryos. The present study indicates an important role of Hrt1/Hey1 and Hrt2/Hey2 in endothelial cells during early vascular development, and further suggests involvement of Robo4 and Src family kinases in the mechanisms of embryonic vascular defects caused by the Hrt/Hey deficiency. Show less

Neuronal ceroid lipofuscinosis (NCL) is a genetically heterogeneous group of lysosomal diseases that collectively compose the most common Mendelian form of childhood-onset neurodegeneration. It is estimated that ∼8% of individuals diagnosed with NCL by conservative clinical and histopathologic criteria have been ruled out for mutations in the nine known NCL-associated genes, suggesting that additional genes remain unidentified. To further understand the genetic underpinnings of the NCLs, we performed whole-exome sequencing on DNA samples from a Mexican family affected by a molecularly undefined form of NCL characterized by infantile-onset progressive myoclonic epilepsy (PME), vision loss, cognitive and motor regression, premature death, and prominent NCL-type storage material. Using a recessive model to filter the identified variants, we found a single homozygous variant, c.550C>T in KCTD7, that causes a p.Arg184Cys missense change in potassium channel tetramerization domain-containing protein 7 (KCTD7) in the affected individuals. The mutation was predicted to be deleterious and was absent in over 6,000 controls. The identified variant altered the localization pattern of KCTD7 and abrogated interaction with cullin-3, a ubiquitin-ligase component and known KCTD7 interactor. Intriguingly, murine cerebellar cells derived from a juvenile NCL model (CLN3) showed enrichment of endogenous KCTD7. Whereas KCTD7 mutations have previously been linked to PME without lysosomal storage, this study clearly demonstrates that KCTD7 mutations also cause a rare, infantile-onset NCL subtype designated as CLN14. Show less

Early diastolic myocardial tissue Doppler velocities have reported to be reduced in mutation-positive patients with hypertrophic cardiomyopathy (HCM) in some studies even in the absence of left ventricular hypertrophy (LVH). Strain is a sensitive tool in detecting early systolic abnormalities in patients with HCM. Our goal is to examine novel echocardiographic characteristics of phenotype-negative carriers for a known sarcomeric gene mutation for HCM. We evaluated 41 consecutive subjects with a known myosin-binding protein C3 (MYBPC3) mutation (c.3330+2T>G). Subjects who were mutation positive without LVH (G+/LVH-, n = 35) were compared with healthy controls (n = 30) regarding tissue Doppler and segmental longitudinal strain measures. The G+/LVH- group was similar to the healthy controls with respect to chamber size, left ventricular mass index, and most diastolic filling parameters, including tissue Doppler-derived early diastolic annular velocities. Global longitudinal strain was similar for both groups (20.3 ± 2.1 vs 19.8 ± 1.8, P = .36), although regional segment analysis showed a notable reduction in the basal septum (16.8 ± 3.1 vs 19.0 ± 4.0%, P = .02) and increase in the basal posterior (22.5 ± 5.2 vs 17.9 ± 5.2, P = .001) as well as mid posterior (21.8 ± 4.7 vs 18.2 ± 3.0, P = .001) walls. In our cohort of phenotype-negative carriers of a specific MYBPC3 mutation, there were minimal differences in conventional 2-dimensional, Doppler, and speckle-tracking-derived parameters of systolic and diastolic function compared with that of healthy subjects. The presence of regional alterations in strain indicative of the presence of underlying subclinical disease requires further validation. Show less

The basic helix-loop-helix transcriptional repressor Hairy-related transcription factor 2 (Hrt2) is expressed in ventricular, but not atrial, cardiomyocytes, and in endothelial and vascular smooth muscle cells. Mice homozygous for a null mutation of Hrt2 die perinatally from a spectrum of cardiac abnormalities, raising questions about the specific functions of this transcriptional regulator in individual cardiac cell lineages. Using a conditional Hrt2 null allele, we show that cardiomyocyte-specific deletion of Hrt2 in mice results in ectopic activation of atrial genes in ventricular myocardium with an associated impairment of cardiac contractility and a unique distortion in morphology of the right ventricular chamber. Consistent with the atrialization of ventricular gene expression in Hrt2 mutant mice, forced expression of Hrt2 in atrial cardiomyocytes is sufficient to repress atrial cardiac genes. These findings reveal a ventricular myocardial cell-autonomous function for Hrt2 in the suppression of atrial cell identity and the maintenance of postnatal cardiac function. Show less

Hypertrophic cardiomyopathy is typically inherited in an autosomal dominant pattern and has a variable age of onset and prognosis. Mutations in the myosin-binding protein C (MYBPC3) gene are one of the most frequent genetic causes of the disease. Patients with MYBPC3 mutations generally have a late onset and a relatively good prognosis. We report here more than 20 Old Order Amish children with severe neonatal hypertrophic cardiomyopathy caused by a novel homozygous splice site mutation in the MYBPC3 gene. The affected children typically presented with signs and symptoms of congestive heart failure during the first 3 weeks of life. Echocardiography revealed hypertrophic non-obstructive cardiomyopathy. These children had a life span averaging 3-4 months. All patients died from heart failure before 1 year of age unless they received a heart transplant. A genome-wide mapping study was performed in three patients. The disease related gene was localized to a 4.6 Mb region on chromosome 11p11.2-p11.12. This homozygous block contained MYBPC3, a previously identified cardiomyopathy related gene. We identified a novel homozygous mutation, c.3330 + 2T > G, in the splice-donor site of MYBPC3 intron 30. The mutation resulted in skipping of the 140-bp exon 30, which led to a frame shift and premature stop codon in exon 31 (p.Asp1064GlyfsX38). We have found a substantial incidence of this phenotype in Old Order Amish communities. It is also concerning that many unidentified heterozygous individuals who are at risk for development of hypertrophic cardiomyopathy do not receive proper medical attention in the communities. Show less