A novel CRX mutation by whole-exome sequencing in an autosomal dominant cone-rod dystrophy pedigree.

AIM: To identify the disease-causing gene mutation in a Chinese pedigree with autosomal dominant cone-rod dystrophy (adCORD). METHODS: A southern Chinese adCORD pedigree including 9 affected individuals was studied. Whole-exome sequencing (WES), coupling the Agilent whole-exome capture system to the Illumina HiSeq 2000 DNA sequencing platform was used to search the specific gene mutation in 3 affected family members and 1 unaffected member. After a suggested variant was found through the data analysis, the putative mutation was validated by Sanger DNA sequencing of samples from all available family members. RESULTS: The results of both WES and Sanger sequencing revealed a novel nonsense mutation c.C766T (p.Q256X) within exon 5 of CRX gene which was pathogenic for adCORD in this family. The mutation could affect photoreceptor-specific gene expression with a dominant-negative effect and resulted in loss of the OTX tail, thus the mutant protein occupies the CRX-binding site in target promoters without establishing an interaction and, consequently, may block transactivation. CONCLUSION: All modes of Mendelian inheritance in CORD have been observed, and genetic heterogeneity is a hallmark of CORD. Therefore, conventional genetic diagnosis of CORD would be time-consuming and labor-intensive. Our study indicated the robustness and cost-effectiveness of WES in the genetic diagnosis of CORD.

Genetic diagnosis of autosomal dominant polycystic kidney disease by targeted capture and next-generation sequencing: utility and limitations.

Mutation-based molecular diagnostics of autosomal dominant polycystic kidney disease (ADPKD) is complicated by genetic and allelic heterogeneity, large multi-exon genes, and duplication sequences of PKD1. Recently, targeted resequencing by pooling long-range polymerase chain reaction (LR-PCR) amplicons has been used in the identification of mutations in ADPKD. Despite its high sensitivity, specificity and accuracy, LR-PCR is still complicated. We performed whole-exome sequencing on two unrelated typical Chinese ADPKD probands and evaluated the effectiveness of this approach compared with Sanger sequencing. Meanwhile, we performed targeted gene and next-generation sequencing (targeted DNA-HiSeq) on 8 individuals (1 patient from one family, 5 patients and 2 normal individuals from another family). Both whole-exome sequencing and targeted DNA-HiSeq confirmed c.11364delC (p.H3788QfsX37) within the unduplicated region of PKD1 in one proband; in the other family, targeted DNA-HiSeq identified a small insertion, c.401_402insG (p.V134VfsX79), in PKD2. These methods do not overcome the screening complexity of homology. However, the true positives of variants confirmed by targeted gene and next-generation sequencing were 69.4%, 50% and 100% without a false positive in the whole coding region and the duplicated and unduplicated regions, which indicated that the screening accuracy of PKD1 and PKD2 can be largely improved by using a greater sequencing depth and elaborate design of the capture probe.

Efficacy and safety of the coronary intervention therapy to prevent electrical storm in patients with coronary artery disease but without myocardial infarction / 中华心血管病杂志

<p><b>OBJECTIVE</b>To study the efficacy and safety of the coronary interventional therapy to prevent electrical storm (ES) in patients with coronary artery diseases (CAD) but without myocardial infarction or ischemic cardiomyopathy.</p><p><b>METHODS</b>Coronary angiography and stent implantation were performed in CAD patients with ES as major symptom, according to the standardized methods. Holter Electrocardiography was recorded regularly during follow-up.</p><p><b>RESULTS</b>Six patients, five male and one female, with mean age of 49.5 +/- 9.1 year-old, were hospitalized. In 2 patients with repetitive syncope, multiple episodes of ventricular tachycardia and/or ventricular fibrillation (VF) were documented by Holter recording. One patient developed VF during exercise test. Three patients experienced chest pain and multiple episodes of cardiac arrest. Before procedure, averaged 16.5 +/- 5.3 episodes of syncope or VF were documented in 6 patients. Coronary angiography revealed severe one or multi-vessel diseases. Total 8 stents, including 3 drug-eluting stents, were implanted in 6 patients. Symptom, ST-T changes and ES disappeared after coronary stenting. During 4 month to 6.5 year follow-up (mean 47.7 +/- 30.7 months), ES was not documented, no appropriated shock occurred in patients with implantable defibrillator for 6.5 years.</p><p><b>CONCLUSION</b>In CAD patients without myocardial infarction, coronary stenting can relieve the ischemic substrate of ES, hence prevents sudden death effectively.</p>