Risk Stratification in Young Patients With Channelopathies

Identifying the young patient at risk of malignant arrhythmias and sudden cardiac death remains a challenge. It is increasingly recognised that sudden death, syncope and aborted cardiac arrest at a young age in patients with a structurally normal heart may be the result of various ion channel disorders - the channelopathies. The approach to risk stratification involves a combination of the clinical presentation, taken in conjunction with the family history, genetic testing, invasive electrophysiological studies or other provocative tests where appropriate and feasible. A logical approach to risk stratification in some of the commoner channelopathies seen in paediatric practice is presented.     

Protein-Protein Interaction Analysis Highlights Additional Loci of Interest for Multiple Sclerosis

Genetic factors play an important role in determining the risk of multiple sclerosis (MS). The strongest genetic association in MS is located within the major histocompatibility complex class II region (MHC), but more than 50 MS loci of modest effect located outside the MHC have now been identified. However, the relative candidate genes that underlie these associations and their functions are largely unknown. We conducted a protein-protein interaction (PPI) analysis of gene products coded in loci recently reported to be MS associated at the genome-wide significance level and in loci suggestive of MS association. Our aim was to identify which suggestive regions are more likely to be truly associated, which genes are mostly implicated in the PPI network and their expression profile. From three recent independent association studies, SNPs were considered and divided into significant and suggestive depending on the strength of the statistical association. Using the Disease Association Protein-Protein Link Evaluator tool we found that direct interactions among genetic products were significantly higher than expected by chance when considering both significant regions alone (p<0.0002) and significant plus suggestive (p<0.007). The number of genes involved in the network was 43. Of these, 23 were located within suggestive regions and many of them directly interacted with proteins coded within significant regions. These included genes such as SYK, IL-6, CSF2RB, FCLR3, EIF4EBP2 and CHST12. Using the gene portal BioGPS, we tested the expression of these genes in 24 different tissues and found the highest values among immune-related cells as compared to non-immune tissues (p<0.001). A gene ontology analysis confirmed the immune-related functions of these genes. In conclusion, loci currently suggestive of MS association interact with and have similar expression profiles and function as those significantly associated, highlighting the fact that more common variants remain to be found to be associated to MS.     

Parental transmission of <Emphasis Type="Italic">HLA-DRB1*15 </Emphasis>in multiple sclerosis

Chen et al. found that the CA haplotype of protein C -1654C/T and -1641G/A was associated with increased risk of death and organ dysfunction in Chinese Han patients with severe sepsis (Hum Genet 123:281–287, 2008). We similarly tested for association of the C allele of protein C 673 T/C (rs2069912) (linkage disequilibrium with the CA haplotype, D′ = 100%) in a cohort of 100 North American East Asians with severe sepsis. The C allele was associated with increased mortality and organ dysfunction, consistent with Chen et al. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Support: Sirius Genomics Inc., Canadian Institutes of Health Research. Keith R. Walley is a Michael Smith Foundation for Health Research Distinguished Scholar.     

Implantable diagnostic and therapeutic devices in children

Many advances have been made in the use of implantable diagnostic and therapeutic devices in adults. In children the indications for and diagnostic and therapeutic value of these devices still have to be determined.Our aim is to provide an overview of the clinical use of diagnostic and therapeutic devices in children. The role of implantable loop recorders (ILR), the feasibility and safety of transvenous pacing in neonates, the value of permanent pacing in children with recurrent syncope or reflex anoxic seizures and the role of implantable cardioverter defibrillator devices are highlighted with relevant case histories.